The only problem I see with British Somaliland is that it was by far the least developed British territory in Africa, the only major exports were hides and skins along with camels, mostly going to Aden, Yemen and Saudi Arabia. The inhabitants were overwhelmingly pastoral and there were only around 250 British in the territory in 1950. The only other place that was this underdeveloped was probably the Barotsesland Protectorate in Northern Rhodesia.
A better option would be to take the Eastern portion of Northern Rhodesia, the northern third of Nyasaland and southern Tanganyika (modern regions of Mbeya, Iringa, Ruvuma, Lindi, Mtwara and southern Iringa and southern Rukwa) and make it a new British Territory in the 1930s. This would contain lots of fertile areas and some highlands with good climates, but with few people There were only around 2.9 million inhabitants in this area around 1945.
In 1938, the Czechoslovak government had petitioned Southern Rhodesia to admit Czechoslovak immigrants, and the following year many Jews from Germany, Austria, Hungary and Czechoslovakia all applied for residency in Northern and Southern Rhodesia. However, the British government would only admit 500 aliens per year.
In 1942, the British government did accept thousands of Polish refugees from the USSR through Iran and sent most of them to Tanganyika and Northern Rhodesia (many to the areas I proposed), with smaller numbers going to Kenya, South Africa and Southern Rhodesia. The USSR released a total of 389,041 Polish citizens between March and September of 1942 through Iran, so sending them down to East Africa would be a lot more expedient than all the way to the Americas or Great Britain.
There had been proposals to make Tanganyika a Jewish homeland along with parts of Northern Rhodesia. The only issue with Tanganyika was how densely populated the northern portion of the country was already (at least by African standards). Therefore the regions in the South make the most sense.
The central portion of Northern Rhodesia can join with Southern Rhodesia since it was the most "European" area of the country and both Northern and Southern Rhodesian whites wanted this. Barotseland can formally become a British protectorate like the high-commission territories, being that it was already governed separately from the rest of Northern Rhodesia and would be until independence.
In June 1939, 309,000 Jews from the now enlarged German Reich applied to emigrate. Very few found countries willing to take them however, with the largest number, 18,000 being able to settle in Japanese-occupied Shanghai. Even as late as November 1939 Britain rejected please to alter the Jewish immigration quota to Palestine.
I can envision this British Central African territory being not only a home for Jewish refugees, but also Poles, Lithuanians, Estonians, Hungarians, etc. Britain had a huge number of displaced persons by 1946, perhaps many of these would be sent to Africa, even if temporarily. By the end of the war the refugee population in British Central Africa could like this:
1945 Refugee Population
600,000 Jews
250,000 Poles
150,000 Czechoslovaks
70,000 Lithuanians
30,000 Ukrainians from Poland
25,000 Belorussians from Poland
20,000 Latvians and Estonians
15,000 Italian POWs from East Africa
I assume many would leave after the war, as Australia, the United States, Canada, Argentina, Venzuela, and Brazil were fairly open to European refugees during the postwar period. However, some would probably be able to establish successful commercial farms and businesses and decide to stay. I can see many being in engaged with trading of goods of neighbouring colonies and territories.
Coffee (around Mbeya), cotton, tobacco and sugarcane could all be produced in this region, so many people who came with capital could establish commercial farms. Lindi and Mtwara would become major ports and a railway could be built to Songea, allowing for a development corridor.
After the war you have a large number of refugees coming from Poland, the Baltic States, the USSR etc to Britain. So another 300,000 would arrive. Perhaps Hungarian refugees are taken in after the failed uprising of 1956.
However, by the early 1960s the question would be what happens to this territory, no doubt the 4-million African population would want independence. If there are 1-2 million non-Africans you have a situation akin to South Africa, which would undoubtedly lead to more conflict in the region. By that time, the refugees living in this area have no doubt become attached to what they see as their land, and conflict may arise with the British government. Perhaps a UDI happens here rather than in Rhodesia.
Rhodesia may get the dominion status its white population just after the war, except now it includes almost all of Northern Rhodesia's white population and just 1/3 of its Africans. The only thing stopping their receiving dominion status in the early 1950s was taking on large mostly African areas in the Federation. It also controls the vast copper deposits of the copper belt putting it in a stronger position economically as copper prices remained high until 1975. Its government may start to interfere in the internal politics of Katanga and promote separatism there by 1959.
British Central Africa may attempt some sort of UDI if its population doesn't agree to one man one vote. If a large enough Jewish population remains there (100,000 or more), Israel would most likely support this state as it did South Africa. If Tanzania becomes independent under the leadership of Julius Nyere, he's most likely still going to support liberation movements for Southern Africa. However, his main target is going to be this minority-ruled country to his south rather than Portuguese Mozambique. Giving bases for a liberation movement to start a guerrilla war with, however such a country could retaliate much more forcefully than the Portuguese ever did, especially if its run by people from states now under Communist control.
Katanga may be able to last as a breakaway state, perhaps with the assistance of Rhodesia and British Central Africa. The Belgians may even hold a referendum there excluding the large migrant Kasaian population and keep it a separate territory, eventually granting independence around 1963-1966 to a pro-Western leader. This would give Rhodesia a large buffer zone.
Barotseland and Malawi become independent in the mid to late 1960s. However, Barotseland becomes much like Lesotho, a poor traditionalist state surrounded by white-ruled areas and dependent on their aid. Malawi too becomes like this and Hastings Banda would most likely still be pro-Western as his economy would be dependent on the remittances of migrant workers from neighbouring states.
The Portuguese territories would gain new buffers. Without Tanzania and Zambia, FRELIMO has no bases to operate from. Therefore, the guerrilla war does not begin in Northern Mozambique in 1964 or Tete in 1969. Without Zambia, the MPLA in Angola has no bases from which to operate from and the war there is effectively over by 1965-1966. This undoubtedly gives the Portuguese army less war fatigue and more time to focus on Portuguese Guinea, possibly butterflying away the 1974 revolution.
In the end you have the ability to save far more people early on, but a messier situation as far as majority rule come Southern Africa as a whole. Especially because South Africa, Rhodesia and the Portuguese territories are now all covered by a "cordon sanitaire".
) with a British socialist "revolution" in 1931 around the time of an Arab revolt - the Mandate goes down in blood and fire 31/32 without British protection so I'm thinking of a Uganda style position in the late 30's. The Palestine position is the most likely, and what the Zionist movement want but it requires both a Britain strong enough and politically committed to maintain it till at least the 40's. Before that the Arabs are strong enough to roll over the Jews, even with various Aliyahs till that point. 
