yeah, if you mirrored the whole drivetrain on the car, the rear diff doesnt care which way its sat, as long as its pulled the same way, the front only matters when its got a 1-way saying im only going 1 direction.
On the kits able to run 6 cells on either side, they should be able to throw the drivetrain the other way around and fit a backwards 1-way (or still run perfectly but without a 1-way).
I just had a look at my 1-way unit, if the mount wasnt just slightly off-center, it could have been possible to just mount the pulley on the other side, however im guessing the tight squeeze they've put onto the '05 will mean that slight bit of off-center the pulley would be in to operate about... 5mm from its correct location, putting it onto the left side, would probably be too far over.
I doubt it would work, but it would be the electrics side it'd be very close to, electrics can be possitioned better, cells obviously cant, so *maybe* thats a possibility, it would depend entirely on what contact was now possible with 'foreign' objects within the car (bulkheads, motor mounts, electrics etc)