Thanks all for the suggestions!
The camera is on the way to Solms as I type this for a thorough going over, including new shutter curtains, rangefinder repair/adjustment, shutter "reawakening" (the slow speeds were very sticky), a thorough CLA of the lens and a bunch of other stuff.
I'm waiting to have the camera back before I make any firm lens decisions -- and I WILL push a few films through the camera before I do anything else -- but I've sort of settled on the 21mm f/4 Voigtländer, though I have to admit that I am mighty tempted by the 15mm f/4.5. Experiences? Anyone got any pictures online they can point me to?