Wheelworks on W. 11th between Lawrence and Washington is the ticket. Take a look at the bikes on display and you will find the owner's Trek from the '70s; he's finally willing to part with it. (It's the very tall green one.) I bring all my '70s and '80s Treks in when I need/want something for them. Bill, the owner, and Kevin, the chief mechanic, are just great to work with. It's a small shop, so the stock on hand is limited, but they usually find a way...
The other shops in town are hit-and-miss, mostly miss. Steer clear of Paul's; they're bad news.