Is there a way I can use a Treo 700Wx with no cell service (otherwise in good working condition) as an interface for a laptop without a screen? The application is that I would like to have a pc in my car (laptop under seat), and use the Treo as a touchscreen monitor.

I'm not sure this is what you are looking for but I use MyMobiler which essentially is the opposite. Maybe they also make another version?

I have a carputer in my car and you will want to have a touchscreen instead of the small cell screen. Even with the "large" 7 inch I have, its still a little small at times since windows is NOT touchscreen friendly.

That is what I am trying to do, basically mimic the 7 in lcd touch screen. I agree about the size to a point, but with a screen resolution set at 800 X 600 I think I could do some basic navigation. I appreciate the feedback.