OK, you guys aren't going to be happy with me...
I've been measuring voltage across the fuse. So, measuring the 12V+ side of the fuse, and grounding to chassis, I'm getting 12.4V across fuses B1 - B4. I measured all the way from the battery, to the fuse box, only to realize my error. What a dope I am.
Anyway, I think I've ruled out the battery, charging system, current distributor, fuse box, and fuses. My next step is to measure voltage at the cluster power connector. If I have 12V+ there, I believe it would be safe to assume the issue is with the cluster itself.
Sorry for the wild goose chase, I know you guys have been getting a headache over this one. Yes, I already put $1 worth of quarters in the ass-kicking machine. If there's any consolation, I'm working my way passed my fears of working on electrical!!!
Do you guys know how the pins are the black cluster connector are numbered?