Hey Trug, I like yer "out the box" idea of mounting the engine inverted.
I have also contemplated the same idea. Not that there's any advantage, but just to be different and unusual. Would sure be a head turner!
If you use RC's idea, you wouldn't have to reverse engine rotation. Just use a chain driven jackshaft with a fricton roller driving the rear tire. Something like this jackshaft.DSC_1530.JPG