'65, big back window and extended cab ??'s

[t_shirtsnjeans]

Ok, I have a couple of '65's, one is GMC (my future project truck) and the other Chevy (parts/donor truck), plus I have a 74 Chevy 1/2ton pickup for parts (discs, rears, tilt, etc) and I was wondering if anyone has put a large rear glass from a later 70's Chevy p'up in a 60's model.
Also, extending a cab using two cabs, possibly chopping it in the process, anyone done that and what am I looking at in terms of cost for the glass? I really don't NEED it chopped, but I really do need it extended, and shortening the bed isn't that much of a chore, saw it on a tv program a while back so I can keep the long wb frame.
OK, last question, since I do have a 74 donor truck, would it be easier and worth it to use THAT frame for my project and toss the 65's?

I know it's a lot to ask, (oh lookie, a VH smilie! ), but perhaps I can get someone, anyone, someone, no one, to encourage me a teeny weeny bit?

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