I think I've figured out what's going on (after careful reading of my home repair book on electricity and rather un-careful blowing of a breaker). I think what I'm looking at is pretty simple--a loop circuit with mis-labeled wires. As far as I can tell, instead of recoding the white wire to black at the fixture, some idjit recoded the black wire to white. So I've got a black wire coming back on the return from the switch, and a white wire incoming from the circuit, and two white wires tied together going from the circuit to the switch.

That make any sense? The switch end only has one piece of romex coming in, so that's got to be what's going on.

I had thought I posted pics the other night, but I think I must have gotten distracted and not pressed Submit...

I am the Doctor, and THIS... is my SPOON!