Wouldn't even be possible, you'd have to re-do how the interior looks to fit a transmission down the center of the car. Plus the exhaust pipe would have to be routed elsewhere and the rear suspension would have to be completely re-fabricated. It would cost you more money making a custom drive system than it would cost you to buy a Corvette...
The Audi AWD system can go all the way from 80% rear to 50/50 if needed.
The Saab XWD system will go 90% rear like they say, but the front wheels have to start spinning (ie. accelerating hard in a turn) to trigger the system to go to it's max. The car is much more efficient as a FWD so it will use those wheels as long as it can. From what I've read, the XWD system is quite stunning in the snow, I'm curious to see how the new 9-5 drives.
I can't wait until someone creates a mod for the ECU that allows the driver to manually select the drive bias...
