There are hundreds of possible materials that could be used, chrome or Nikasil wouldnt be very high on the list though (the BMW issue was partly ethanol related)....... You will find that the better coatings are plasma sprayed and then ground, usually onto a prepared (bored and blasted) aluminium bore, this leads to one potential sticking point with a Norton and that is the bonding of the coating to the cast iron, a nickel-aluminium bond coat may be required first. Cast iron is a very good wear surface but some of these sprayed coatings are so far ahead in terms of wear that it is not funny. As ring materials have also been mentioned it is possible (probably preferable) to use thin coated rings (TiN etc), these may not be of such an advantage in a Commando but in high reeving engines the reduction of mass in the top ring will significantly reduce the stress on the top ring land.