I did the sandpaper mod to my d-pad. Works a lot better, but still nowhere near perfect. If the next round of sanding doesn't solve the d-pad's insistence on doing an Ice Shower when I try to uppercut, I'm going to bite the bullet and buy a custom stick from
http://home.comcast.net/~dreadedfist/.
He made a stick for Gamespot's Dave Toister. I asked Dave about it, and he said it cost about $120 and the guy who makes them doesn't do the soldering. Here's a picture of it.