The only thing I know of that is still active is TheBitMines.com.

But they changed (for obvious reason) from paying you for mining/setting certain blocks to making the ingame economy bitcoin based.

Quote form the Site:

"> The Bit Mines is a Minecraft server that uses Bitcoin (BTC) for its economy. You can buy or sell items in-game, claim and sell plots of land, bet on PVP tournaments, bet on Spleef tournaments, and so much more - all with BTC."