[Max Lobovsky]

I have been considering ways to make a drive train like you are describing (and i have thought of the one you suggested) and i came to the conclusion that that method is to complex mechanically. As you can see from the reversing gear box that you put in the post you linked from, the reversing system is quite complex. Basically, i dont think its practical. As jim said, what you described is basically a swerve or crab drive is much more do-able (and has been done).