I think that it would be a wasted effort,they are an orphan bike with very little performance potential and as a Cafe racer the shaft drive let's it down.it is my opinion that apart from a couple of racing XS1100's i have not seen a really trick XS1100 on the street in Australia,they have a lot of potential and with a chain drive and later model front end would be a real road eater and would not be that costly.
Regards Dale