I've been thinking about this for a while with decentralized and trust-less at the top of my list.

I think a solution based on serial micro-payments (or similar) makes more sense and will protect the trust-less decentralized nature of P2Pool.

Today I saw this video, it's "Lecture 3 - Mechanics of Bitcoin" from the Princeton University course, the link starts at 34:30 where he starts to talk about serial micro-payments.

His example is for by the minute telephone billing, it's not the actual solution for P2Pool, but pretty close (I hope)

If you watch, in his example, replace Alice with P2Pool and Bob with a miner...

https://www.youtube.com/watch?v=t3hJsFpPmXs&feature=youtu.be&t=34m30s

I guess my first question is can anyone tell me why something like this would not work?