What discount to expect on special-ordered truck?

It's all a Numbers Game, % off MSRP, more for your trade than it's actually worth. The bottom line: If it a deal you can live with. Use internet sources such as Edmunds and work up a Dealer cost, then the MRF's site and work up what the list would be, figure out what you need for your trade and work the numbers to get a fair value. If you go into a Dealer and say I want that Truck, you're at their mercy. Do your research first.