The more I research this the more I am convinced this is somehow possible. People on other message boards have been able to get their phone to recognize a usb thumb drive via a modified usb cable and as I posted earlier someone made a touchscreen work with a HTC Advantage using windows CE touchscreen drivers. The following is some links to some info I have found so far:
http://forum.xda-developers.com/showthread.php?t=411905
Post at xda developers discussing usb host on the touch pro.
http://forum.xda-developers.com/show...89&mode=linear
Another post at xda discussing using a usb keyboard with a diamond
http://handheld.softpedia.com/get/Sy...er-35283.shtml
A link to software that claims to give you a mouse pointer on your USB host enabled PPC.
http://wmpoweruser.com/?p=490
An article about the possibility of usb host on the diamond.
There are a few more things I'll post later.