Just my thoughts,
What about a direct drive motor with belts as your going to be adding belts anyway? Would be a lot quieter. or just direct drive and mecano?
I was going to use the MMt12 with mecano for my Talisman and Waverly (until i lost interest in both of them)
Dead easy to find all the parts on ebay.
Quiet with bags of torque and a scale like speed - top end speed and low end speed being adjustable using the electronize speed controller wich i have to say are my fav controllers.