I want to use a set of 200mm cranks a touring bike, and I'm looking for a classic frame to start with.
Ideally I'd like it to be a rigid 26" MTB.
The problem with 200mm cranks is the risk of pedal-strike during a turn, AND heel strike when the heel of your shoe his the panniers behind you.
I have a modern 700c frame with a BB that is nearly 300mm off of the ground, but heel strike remains an issue.
Ideally the BB height would be something around 290mm or higher. Wheel size affects this - I'd be running semi-slick tires around 26 x 2.0" size