Later and higher end models did have canti brakes. Cannondale trickled them in starting in the late '80s and then brought it down through the whole line (my '90 ST400 has them). Low-rider bosses were present right away, though excluded on a model here and there (don't know why). You can use them for touring for sure, but if you need a bike that still has to accelerate or work out of the saddle, these behave like a race bike--no whippy-ness or slop.
Vintage brochures are always your friend if you want more info. 