I don't know why I hadn't thought of this sooner. My Palm TX had a pretty broken touchscreen, with large unresponsive areas in the middle of the screen and in the graffiti area. I had been coping with this for years... writing really small and frustrated graffiti in the corners, and creatively using various combinations of presses around the edges to activate buttons in the middle with touchscreen averaging.
But after replacing the broken screen in my wife's eeePC a few weeks ago (it was only $50 for a beautiful new glossy screen) I thought I might try buying a replacement Palm touchscreen (which go for about $20-$30 and include the special * screwdriver). Then I remembered that I had my old broken Palm T5 lying around, which still had a nice working touchscreen. I don't know why I assumed they wouldn't be compatible earlier...
Anyway, the small bit on my leatherman fits the Palm T* screws fine, and after a bit of drunken internal surgery, the transplant was complete. My Palm TX has a new lease on life, with a nicely calibrated touchscreen and hard buttons on the front that work consistently now.
Of course, now I have to invest in some better protective gear to keep it that way... my jacket pocket just contributes too much lint.
Unfortunately, the power button still doesn't work, but there are apps to compensate for that, like PowerBtn or OffStroke.