If the touchpad Go's navigon app can be leaked, perhaps it could be tweaked a bit to work on the Pre3!
Someone leak it! Please! Anyone in HP who reads these posts, leak the Touchpad Go's Navigon Garmin app so we can play with it!
Why don't you go a bit more ambitious and hope that there are actually produced units already and hope they sell them to HP employees who in turn will throw them on eBay?
They were set for fall 2011 so I wouldn't be surprised if there indeed are a few lying around. Heck Foxconn does still have the parts for it.