I found what I believe is a 1987 Miyata triple butted mixte frame in a 54cm for my wife's bike. Miyata made the same bikes for Univega so there are some "lighter" mixtes out there. They are about a half pound more than the same bike in a diamond frame. Just going to 700c's I have room for fenders and larger tires on hers. The hard part is finding one biger than a 50cm. Ron