Go for it! Here's my Raleigh Touring 18 with the canti studs moved down 23 mm (630 to 584) to fit 650B wheels.



Just remember- you'll need to repaint around the canti studs, and not all canti's will fit- you need to find some older ones like Shimano AT50's or Dia-compe 981's since the spacing will be much narrower (55-65 mm) than normal MTB (>75 mm) spacing. Some V-brakes are OK, too, but then you'll need "travel agents". See what brakes older touring bikes use, and find a pair to use for locating the studs. I used Nova 7 mm offset for the front and 13 mm offset for the rear. They required very little filing. Also it's a good time to add any other bottle bosses or chain hanger bits while you have the torch out.

Good luck, and be sure to post pics!