Fascinating discussion, gentlemen. Thank you for expanding on the differences in Toyota truck frames. It's curious that the frame under my 2001 4Runner appears to be boxed from bumper to bumper. I'll admit, I am partial to the styling of the Tacoma. You are right that with enough money you can make anything happen. But given my available funds, and lack of expert metal-working skills, I'm looking for a mostly bolt-on options. I will have to pay an expert to extend, and possibly box-in, the frame. There is at least one company that does RV frame modifications here in southern California (http://www.ocrvpaintandservice.com/). Given the potential liabilities, I can't imagine many reputable shops would want to do in such work. Ditto with custom building rear axles.