Update:
I went ahead and had the valve stem seals replaced and have since gone over 1000 miles without needing to top off the oil. This represents at least a 10-fold improvement. I've noticed some sluggishness with the response when trying to accelerate, but I'm not sure if this is just the nature of the smaller 6-cylinder engine in such a heavy car, or if there might be some additional clean-up work to be done... maybe the cat converter (from earlier oil consumption), oxygen sensor, fuel pump... any ideas? I replaced the plugs already and she runs smooth. Car fires up great first time every time and has never stalled,so doubt any kind of ignition issue... just sometimes slow to respond to depressed pedal. She's got 105k. Apart from this, I think I've finally got all under-the-hood issues resolved (knock on wood), so now I've got her in the shop for a little exterior touch up. A little dashboard repair and some new rims are next, then, finally, maybe I can get some pictures up onto the 126 roll call.