yes, I've gone that route in the past. Had an early 80's Specialized Sequoia that I just loved, fit me perfectly at exactly 52 x 52. Harris Cyclery in Boston coldset the frame for me so I could put an 8 spd cassette in the back. I've also converted a Terry Classic to 650B with long reach caliper brakes. But the calipers just haven't worked for me in the Portland winter weather and the front forks have been too narrow for fenders and the winter tires I typically throw on to make it through the pine cones, gravel, nails, and other crud in the bikelanes. So that's why I'm looking for something with a wide enough fork for at least 35mm but preferably 38mm tires and fenders.