I cut the frame the same way Stacy from Trucks did. I followed LFD's "how to" on cutting down the bed sides:
Starting on page 8
http://67-72chevytrucks.com/vboard/s...=223158&page=8
The best tip is the little screwdriver that LFD shows in post 201
I priced out using aftermarket bedsides, but I think it was like $1400 to get them to my house. No install or paint work.
Just remember that everything needs to be shortened, exhaust, driveshaft, brakelines, wire harness, etc
It took me and my father (visiting from NY) 2 full days to disassemble, cut, and reassemble the truck.
Here are some pics:
1st layer of body work
More recent with bed in epoxy primer