So it works!
So I called Kennys Trucks a couple of weeks ago, a place several had recommended as having the 3/4 ton hoses. I called and ordered them. They called me back about an hour later saying their supplier no longer has/makes them, but he will find me something that worked with the length, etc needed. A couple phone calls and some texted pics later he said he was pretty sure he found what I needed.
I googled the PN I got, and it seems they're available from Summit, as 69 Camaro/Firebird and/or 69-72 Nova Hoses:
http://www.summitracing.com/parts/rsd-fh03
The P/N is FH03
From where they mount on the frame they are a full 3" longer than the stock 71/72 C10 truck hoses.