Ummmm if I'm reading you correctly your saying the trackpad can be modified to connect to the Tour? Good luck trying to modify all of the front casing + keyboard + etc.
Something likely feasible for RIM but very unlikely to see running in the wild unless it was a test berry from early production. I vote unlikely to see in the wild.
Posted from my CrackBerry at wapforums.crackberry.com
im def looking forward to trying this when the 9700 trackpad oem parts get released online. only one way to tell for sure if a software update stands in our way...