Over last weekend, I played on a Robotron with 3"shafted leafs, and not-to-firm centering grommet, that makes me take back my 'I hate leaf-switched sticks' statement. I was making some NIN-JA-like movements with them. Most of the time.
That said, I'm still hard-pressed to give up my P360s. They are somewhat modified, along the lines of kowal's ideas though before I came to his info site, and have less travel and register sooner than stock. Not as soon as I'd like, and yes the spring is a little tough. If I could get the U360 set up well enough, I'd replace the P360 with it so I could get the middle stick out of the way and all.
Of course, I've bought my P360s for no more than $32 a piece on ebay. And on that note, damn that's a cool - and un-surprisingly un-HAPP idea'd - design kowal linked. And priced right. Those are Comp bases, though, right? I'd have to seriously mod them to tone down the wild-ass throw....which means a thicker actuator at the bottom to make up the distance.