Usually an H bridge is used for forward and reverse. It is pretty much what you describe, only using two more fets. Microchip has an application note about one here: http://ww1.microchip.com/downloads/e...tes/00893a.pdf . It shows a nice diagram of the different states of forward and reverse on page 3.

In your post, I don't understand the " It could steer the correct MOSFET signal with a third 'direction' output." part though.... Don't you steer with a servo?