like that first pic, (i had idea before i saw it) an pannier on the front which has the engine on, and a belt running down to the hub with a cog......however cog on front wont fit?
do it on the back then....and somehow get (if ur single speed) another cog on the hub, which holds your engine powered chain.....powering the rear.......and u can still pedal if you want.......the pannier would be easy to take off, with the engine fixed to it, and just undo the chain???? or tie to the frame lol