http://vanitypool.thruhere.net
The mining interface is compatible with the split-key miners that have been posted through /getWork and /solveWork (or any URLs close enough to those). I have been playing with other data formats accessible by adding a version number to the request, but don't have any fixed version other than the default at this point. The server fee is currently set at 5% or 0.001 BTC, whichever is higher, and the bounty value shown in the /getwork list takes the fee into account so is the actual amount the miner will receive for submitting work for that line first.
Still on the todo list:
Check pattern requests for feasibility before accepting payment
Feel free to share any other feature requests/problems and I'll see what I can do.