that won't work - it'd only work if the "reverse" gear was a higher gear ratio than the "forward" gear. Otherwise, it would bind up.

Think about it: if your reverse side is half the gear ratio of your front, and you're going 10mph, pedaling at 40 rpm (cuz thats the gearing you have on the forward side) the the "reverse" side is going to forcing the left side crank to pedal at 80rpm. No workie.