At the risk of looking as foolish as B-MAg
I have actually raced a car with a one-way in the back and a ball diff in the front
This was many years ago (late 80's) in Australia when the Mid Optima had a one way option - you could simply take the one way unit out of it's housing and place it into the housing of a standard rear gear diff.
On our slippery track I found it worked rather well - front wheel braking stopped you from spinning out into corners and the car wouldn't understeer out of corners as much.
Not too convinced on how well it would work today though
In fact, I'm sure Gil Losi Jr tested a Yokomo Dogfighter with front AND rear one-ways back in early 87 at some big international event at the Romsey track over there, prior to the 87 worlds?