I was in my lbs today, Bernie Jones Cycles and somewhere in the conversation, the mechanic mentioned that they'd just taken a Shimano600 groupset off a wreck. It's a very old groupset - plain chrome and has that 'antique' look to it, but everything is labelled Shimano600. I saw it as it had come off the bike and it needs some cleaning up, but for someone wanting to build up a classic ride, it'd be an excellent start.
Then he mentioned that they've got 'new' bits upstairs too
there are reasons I like this shop