by that logic, Kiev should have worshipped Odin for the next thousand years -- the Vikings were closer than the Byzantines were.
Umm... no? Consider that with Vladimir's conversion in 988, Christianization of the Norse was already under way. Also, Constantinople is quite a bit closer than Sweden and Norway... I am speaking as someone who was born and raised in Kiev (the very same city as the one in question). Kiev's wealth was due to being situated on the trade path "iz Varyag v Greki" (literally, "from the Vikings to the Greeks"), and ironically enough, Rus pagan pantheon was quite close to the Norse one. Even more irony... the Rurikovich dynasty were of Norse origin themselves that by Vladimir's time practically assimilated to the Russian culture.
Plus, another factor remains. While the Rus might have been impressed by the Norse battle prowess, it would not have been much of an impression on them... given that the Rus themselves were assimilated Norsemen, they were not particularly impressed by Norse culture as something to astonish them. Byzantium, on the other hand, at least accordingly to the accounts of ambassadors sent by Vladimir, was another story. Those ambassadors, for example, recalled the service at Hagia Sophia on the account of their arrival as "being of such spectacular beauty that they did not know if they were in heaven or on earth".
also depending upon how much Vladimir valued the independence of his kingdom, and whether he wanted to risk it having to bow to a foreign Emperor (if Byzantium was that close, as you suggest, surely there was the fear in Vlad's heart of Byzantine troops marching through Kiev against him)
Hardly so. If you are familiar with what actually happened, you will note that despite its apparent power, Byzantium is in a middle of civil war at the time. While Kievan Rus did border Byzantine province of Chersonnessus, it was not a situation they considered particularly dangerous - Byzantine interests, other than commercial ones, tended to lay in Italy and Middle East, not in the territories the old Roman Empire never claimed.
Also, note that Basil II's Varangian Guard was in fact almost completely composed of the Rus warriors loaned to him by Vladimir - in fact, Basil II was quite dependent on Vladimir to help him win the civil war, and as a result, there could have been much admiration of culture of Byzantium by the Rus, but not as much fear. Besides, there is wealth that the Rus thought was quite hard to take through any raids on Constantinople, but that was probably Kiev's most profitable trading partner.
Finally, there is another factor that you would need to overcome if you need to make conversion to Islam a viable alternative for Vladimir. Consider that there were already precedents of Christian rulers of Kiev (Olga, in particular, as a regent for fiercely pagan Svyatoslav - Vladimir's predecessor). This leads one to believe that Christianity was already quite widespread in Kiev and beyond, to a much greater degree than any other religion. When all of these factors are taken together, it only leaves Orthodoxy and Catholicism as the only really viable conversion options for Vladimir. So, most, if not all of these need to be altered to seriously bring Islam into picture, alcohol and pork or not.