It would be great to have an app that adds an on screen keyboard as an alternative form input. That would come in handy with older systems that leveraged a full keyboard like amiga, c64, dos.
My experience with touch screens (besides the iPod touch) is that they are not very accurate or sensitive. They can also get in the way too if they are not already predesigned for the device. I don't know, I'm frustrated with the touch keyboard on my lg versa. So the manual keypads should be sufficient (for me anyways, I can't speak for anyone else). I'm sure someone will design it for you if you are persistent enough (or you can ask how to design it yourself). Sorry, I didn't mean to be rude or confusing in the above post. Good idea.
I'm talking about amiga/c64 games here. The virtual keyboard thing is a good start. I think what I'm thinking here is, a side menu that allows you to trigger open, and quickly select a choice of other keys.
In WizCap32 (Amstrad CPC emulator) there's the 9-square "keyboard" already implemented and it works like a charm, mostly because it can be even used without the touchscreen, and I really felt like it was the best way to get a keyboard in a computer emulator. It might get a little bit to get used to, but after a while typing with it (using the touchscreen) it gets pretty fast.
My experience with touch screens (besides the iPod touch) is that they are not very accurate or sensitive.
Although the Wiz's touchscreen might not be perfect, I find it pretty good. I can even type in Termula's micro-keyboard with little to no effort, and I have pretty shaky hands.