Hey bump guys!
Id say its worth more than 3500!
I just did the 3.4 swap on mine too, haven't reffed it yet since i don't have to until december 2010
But for the ammount of labor involved/newer motor/some suspension mods..
Id say $5000 would definitly happen if you found the right buyer.
Good luck with your ventures.
(im wanting to trade mine for an equally built truck too)
-Mike