When you say htat you want to stretch the cab, I assume you want like an extended cab. I never did that, but was planning to use two cabs. I coul use the window channels to make rear windows for the extended part. Also thought about making the doors longer (like a two door car) to make it easier to get in and out of. If you have a second cab, I would think you would have plenty of parts to work with that would match up.
