It is no secret that I am a big (tall) fan of Cannondales.
I own a bunch of them. 63cm and 66cm frame race bikes, 25" and 27" St or T series touring bikes.
I went to the 63cm frame back in '86, leaving behind a 27" frame Fuji Royale. (Tho I still have 2 of these.)
You can usually find the 63cm SR's or 25" ST series bikes/frames around.
I also have and really like a Leader Bikes LD717R aluminum frame in 65cm. It is a nice, fast ride!
Leader does not offer that frame any longer, but they have steel 65cm frames available:
http://www.ebay.com/sch/i.html?_trks...at=0&_from=R40
Keep an eye out on Ebay or CL and they pop up.
wrk101 is correct,tho, that many sellers do not know how to correctly identify frame size, so see a pic or
better yet, see in person if possible.
A point of interest: your Schwinn probably has 126mm rear dropout spacing for 6 or 7 speed cluster.
If this is the case, you will need to respace the rear wheel if using a newer, 130mm frame.
The older ('80's) Cannondales are 126mm.
Good luck!