While awaiting divine inspiration on removing the crank pulley, I thought I would do a little more troubleshooting.
(forgive my numbering convention, if it's not technically correct...1 is in front, 4 in the rear)
I loosened the main bearing caps one at a time, starting with #1 and working my way to the rear. When I loosened #4, I could turn the crank. I re-tightened #4, and went back to #3 and loosened it again...no turn.
I pulled the #4 bearing cap, the crank itself was shiny and smooth, but the surface of the bearing was dull and somewhat rough. I pulled all the bearing caps to compare them (at work, we call this an Air Force check). Here's what I found:
I would have expected the bearing surfaces to be smooth and shiny like the crank. All the bearings exhibit some degree of surface action. It almost looks like galling to me. The crankshaft itself looks very smooth and shiny at all locations, with no surface features that correspond to the condition of the bearings. Rubbing the discolored areas with a finger has a rougher tactile feel than rubbing the exterior of the valve cover.
All I did for the photo was to wipe them down with a shop rag. I haven't done any rubbing or cleaning to the bearing surfaces, other than feel around for the roughness that you can see in the photo.
While this seems to be the problem, I do not know the cause. All components had oil on the surfaces, so it seems they were getting lubrication. There wasn't enough coolant leaking into the oil to turn it milky, so I don't think the oil's lubricating qualities were compromised.
Of course, now I've screwed myself: with the bearing caps out, the crankshaft will turn...I'll never get that stupid pulley off now! Once I can remove the crank, I'll be able to see what the upper half of the bearings look like.