Well finally made it over to ls1z28's to do a Tech II scan, etc.
Fuel Pressure: ok at around 58~psi
Scan shows #8 missing quite a bit. Turns out to be an injector sticking. I think all he did was check that it was firing, probably a little bit of a continuity problem.
Then I put in a can of Sea Foam in the tank (that stuff has got me out of a couple binds) and she purs like a kitten again. Many thanks Paul!
When I have spending money again, I'm going to get a flow matched set from our pals at InjectorsPlus.