Not sure if it would properly interface with the RMK through bolt style one. I know plenty of companies make 4 wheel billet axles. I Think IceAge, TKI, and another company or two make some. Then just order 2 more OEM wheels and your good to go.
That should definately help with the track rolling off the side. Its still going to wear, but should do it less. I know on my one axys the hyfax are worn in a curved pattern in the back.