Thank you for this thread, rhm. I see lots of possibilities for me.
First, I have a 58cm Surly Cross Check, and I'd like to replace it with a 56cm Cross Check only.
I have a bunch of frames:
54cm Peugeot UO-8 which needs alignment. Market value: $0 or less.
68cm Nishiki something or other. Not high end. Yes, really 68cm.
I can't think of what else. I'll take inventory...