We have established a design to follow basically consisting of the front end of a adult mountain bike with two full suspension bikes added out behind.
The rear rider will be powering the rear wheels by way of the main bike bottom bracket drive system. The rear wheels will be attached on a through axle mounted in the two sets of drop outs in back.
The front rider will power the front wheel with a direct drive, much like a children s tricycle. Drawings and 3d model to follow.
Our Community Bikes on Main has been able to hook us up with components and goodies that will make this whole process easy peasey