You must love your truck a whole ton. I'd probably just buy a new one. lol
New trany ,new frame, rebuilt engine, up graded brakes, new bed, new core support, new fenders, inner and outer, New springs ,front and rear. all with in the last 4 years, so yea I like my truck and swapping a cab is not that big of a deal. Up here in NW pa they use salt like it is free and it is very difficult to find a truck that is not a cancer ridden shell.
I am of the camp that I know what i have and am willing to maintain it as opposed to taking a chance on something that i don't know the history of. If it was as easy to find a rust free unit up here as it is down south i would have several of them in reserve.