You should totally just "hack" a Xbox gamepad PCB and build one from scratch. Literally, the hardest part is finding the case to build it into, SRK guys, busy as they are, should be set up to make them in short order.
Guess this doesn't help your short term needs. Umm... you could buy one of those damn Nuby's SF:AC sticks that people insist on making threads about. Or the Hori. Deal with what lag (if any) the converter brings for the time being, and afterwards, when you have ordered\built a better stick, you still have a respectable Japanese stick to fool with too.