Just to close the loop here: I'm all set.
I ended up buying the GM replacement "kit" (GM part #22932565 for a 2500HD crew cab 6.5ft box). Turns out the kit was pretty well available everywhere (Summit, Jegs, even WalMart). I got it through a dealership here locally since it was within walking distance.
Bleeding was no problem. I was able to gravity bleed to get started and then did a vacuum bleed. I've been driving it for a couple weeks now and will probably go back and do one more pressure bleed when it is convenient.
The pre bent lines were nice, for the front. For the rear there were some tight spots behind the fuel tank, crossing over the rail and under the rear wire harness bundle. I think it would have been easier for that to be a straight line and bend to suit under the truck.
Hardest part about the whole thing was getting the stuck brake bleeder screws out.
K