I know this question must have been asked and answered previously, so if anyone knows the thread, please, link me to it, but: If I pick up a frame with 110 mm rear spacing, is there a way I can use my old 120 mm wheel (DA 7600 hub) on it, or is that more trouble than it's worth?
~53 cm, but i might be able to buy a frame--with the troublesome 110 rear spacing--for a couple hundred bucks. It's used, of course, but it seems solid. Problem is, i don't have a wheel that fits it. Oh well.
Just respace the rear to 120 mm, buy a $12 axle and a pair of 5 mm spacers, and file the rear (and possibly front) slots by 2 millimeters in the rear (1 millimeter on the front) and you'll be golden. Yes, there are numerous threads about this. Respacing is just brute force -- grab and pull apart, but go carefully because it'll move more easily than you'd expect. As for filing, a flat file (preferably a draw file -- an industrial supply will know what you are looking for -- and it's cheap at about $7) and a chainsaw chain file for the curved parts and you're golden. Filing will take less than 20 minutes. Then everything is standardized.
As Ceya said, you can get a frame to fit your hubs, but then that frame is always limited to a hard-to-find hub size. It will go up in value quite a bit just by modifying the spacing to 120 and then you can use most hubs and wheels.
Before you spread the rear to 120mm, I would take the time to evaluate the frameset. If it is 110mm spacing then it would be an older frame. Is it rare? Valuable? If it is older it might have "pencil" stays such as my 1938 CCM six day bike, and you would NOT want to try spreading them!