The cable comes out the non drive side on the Q100 but it comes out the drive side on some other motors. Also the cable folds down quite close to the axle end (there is usually a slot) so folding should not be a problem.Have 135mm rear so think a rear hub could work but I may not be able to fold as it folds on the side the cables leave the hub. So best option maybe a mid motor which I don't think will obstruct folding. Regarding battery I have rear rack so anything could be adapted to fit that or alternatively the drink bottle mount on the horizontal folding tube (would it obstruct folding?)