I’m having the same issue. I just bought the tx2500z with 4gigs of Ram and 64bit Vista for $796 after tax and shipping. Smoking deal. But for Zbrush, what to do about that darn ctrl shift and alt keys that seem essential for a lot of functions.
There are mini keyboards out there, hopefully no bigger than your hand, or special gaming keyboards with configurable keys that are a lot smaller.
Right now I’m looking into my iPhone. There are several toubpad/keyboard apps that let you control your computer. But the first one I got exposes a problem with this. Using the ctrl key, shift, etc on that iPhone app is not live. While holding down say the letter A would cause a constant stream of A letters to the computer, the ctrl key didn’t work the same way, it sits there glowing until I tap another key, like O, for ctrl-O, which worked in Zbrush.
So I hope to find one that does true live responses to ctrl and alt and shift. Prices vary from $2-$8, so not much to risk. The guy I bought an $8 one from has offered a refund from paybal. But his is still incredibly usefull as you can create custom sized buttons and record keys into them. So you can record ctrl-S, then label the button as Save, or even a string of characters, like an e-mail address. All the F keys are there, arrow keys, and so on.
On solution I’m pondering if there is a way to remap some useless keys in Vista, like PageUp, Home, End, that I never use to then act like ctrl. Then maybe the iPhone app would have some success and Zbrush would never know the difference. Maybe some software called AutoHotKeys will do that.