a good Russian cause?

This is the main problem. Charities and other forms of centralized philanthropy are almost non-existent in modern Russia -- perhaps because most potential donors are wary of scams posing as charities. Almost everyone here has been a victim of some sort of scam. Most of the everyday philanthropy here is decentralized, flash-mob style -- someone posts a help request with a story and an address to send money, and others re-post it on their blogs if they feel that the request is genuine.

Even if I could find an American supporter (I think I can) and a charity (which will be harder), I still doubt that this will make me eligible for any tax benefits here.