I'll put up one Bitcoin in bounty for a CPU-miner (standalone) that will run on both windows and linux and outperform the built-in miner.
How much does it need to outperform it?
I'm looking into possibly adding support to BFGMiner.
So there's gonna be GPU mining?
Problem is it would be hard to compare, I plan on getting two identical machines, running them side-by-side, and every 2 minutes asking each for their hashrate, then averaging it over a 6-hour period.