What about foreign assistance for the Chinese?
What if Russia aided China in the first or second opium war?
The Great Game was not at its height by the time of the first opium war, but it had started. Possibly the Russians could help the Chinese as a move within the international rivalry
Russia's goal would be to shut out British power, and prevent the British from making another India out of China. Massive openings of Chinese ports also threaten to completely eliminate the residual profits of the overland trade with China.
What was state of Russo-British relations in 1839-1842?
Cooperative in the Middle East, where London and St. Pete both supported the Ottomans in opposition to France and its support of Muhammad Ali.
http://en.wikipedia.org/wiki/Second_Turko-Egyptian_War
However the Russians and British were already at odds in south and central Asia, finding themselves on opposing sides of the first Afghan war, contemporaneous with the opium war.
http://en.wikipedia.org/wiki/First_Anglo-Afghan_War
Reaching a little further back, they had some trouble to.
Britain and Russia had disagreed over Poland in 1830, and over the Congress of Verona, and French intervention in Spain, between 1821 or so and 1830. At the same time, in the 1820s, they collaborated over Greece.
Britain's Second opium war was 1856 and 1860. Russia was too busy, at least in the least 1856 version, to participate, although that was because it was fighting Britain at the time.
What type of aid could the Russians have provided the Chinese if they chose, particularly over their invulnerable, but thin ground supply lines? Some advisors on artillery and some pieces, especially some lighter kinds, a cavalry contingent? Depending on how bold they are they can do some smuggling by sea.