I was looking for something myself. I considered writing my own, but it would take time. Especially if you want it determine upon experience, level etc. I ended up going with the ORK framework (its not cheap), at 100$. But it is very extensive and can manage levels, experience, hit points, character classes, etc. There is also a playmaker action set for it that is extensive (300+ actions).
If you find an alternative, feel free to post it (even if it doesnt have playmaker actions). As those can usually be made if nessesary.