I don't think bed liner is a good idea on a frame, just can't find the words to explain why...
(Edit) Here it is, DeLorean frames were epoxy coated:
http://www.pearce-design.com/PFCheckForRust.html "Did you know that your DeLorean may look and drive like new, while rust slowly destroys your frame? Your original DeLorean frame was coated with an epoxy compound to protect it from road debris and chemicals. However, over time this epoxy breaks down and cracks begin to form, allowing moisture to become trapped between the coating and the metal chassis. This causes accelerated oxidation - in other words, rust. Rust has weakened the structural integrity of some DeLoreans to the point where they actually collapse during normal driving conditions."
I had my frame powder coated, and I do think that is a good idea.
Bed liner sounds like a good idea on the undersides of the cab and fenders though, I've already talked to the line-x folks about that. They already coated the end of my aluminum fuel tank right at the rear tires.
Galvanizing sounds like a good idea if it can be done without distorting the frame. Don't think I'd want to box the whole thing just to get it galvanized though. Boxing a frame that wasn't designed originally as a box is complicated to do it right, if it can even be done right.
Grigg
