I've been looking for a way to use my Palm treo 650 as a carputer for a long time now and finally gave up because it does not have the power/functionality that I needed.
I have since built myself a nice system, but have been searching for a good solution for input devices.
I'm an avid DIY'er so I'd rather use what I have laying around then buy something new.
I thought about converting an old laptop keyboard, and found this site for how to do that.
After reading through that site, I though I should be able to do the same with the treo keyboard as it is pretty much just a smaller form of the laptop kb. So I started reserching and after seeing many posts from people looking to do it but not actually finding anyone who had found it, I stumbled across this:
The short, you'll need to run the pebbles.exe on your carputer, and run the Remote Commander on your Palm. This allows full use of the palm kb to controll the carputer, and the palm screen controls the pc's mouse.
Took me 5 min to setup, and worked first try.
More detailed instructions are available on the pebbles site.
So there you have it 2 solutions for small kb.