I would like to connect a small form factor PC to the aux A/V input on my unit. As far as video and audio this shouldn't be a problem at all. My question is more about the touch capability itself. Would it be possible to somehow forward the touch screen output to USB so that it could be used as a HID device instead of a mouse or other pointing device?

No.

You probably want to look at something like a lilliput screen.

http://lilliputweb.net

I know they have screens for this, I was just hoping to use my Z140 since I already have it installed and don't want to lose it's functionality.

yeah, i was wondering this too. i guess the pioneer is not at that level of letting the user go that far.