Okay folks, after all this I figured the least I could do to let everyone know how it came out, and to help others who might be working this issue down the line:
Today I pulled the head. The head gasket looked okay, although pretty thin. I cleaned out all the water channels, which had a little bit of crud lining them, but not much. Replaced the head gasket. Fired it up.
The head never got above 110 degrees. Plenty of water coming out the exhaust bypass. Ran like a champ.
So, after all that, it was a head gasket issue. I never saw any water on the plugs, so didn't think that was the case. But as they say, it's always the last thing you check.
Thanks again to all who helped out.