It usually boils down to 3 options, pulley, toothed belt and gears. I've used double pulleys but would only recommend then for small low powered drives. The toothed belt and wheels work very well and are reliable, but cost more. We'll worth it in my opinion for the reliability.
The only proviso for belt or pulley drives is that the paddle shaft can be removed occasionally for changing the belt, that's a sensible thing to plan into the design anyway.
Gears are sometimes used, a friend of mine uses them in a Waverley. They can considered a bit loud by some people, but I find that when the superstructure is on and the model under way, it's not a problem.
Belt drives can be bought from MFA como drills and they have a pdf with the range to look through. Gears I'm not sure where to look, but an internet search will turn something up, or another reader will know somewhere.
Chas