I can't think of anything other than GB or XBR SJ wheels that will fit straight in and they are rare and expensive when they come up for sale. You could probably get others to fit, but it would need a fair bit of messing around to get it to work properly. fronts would probably be more difficult than backs, you would probably have to get a big trailie wheel and fit a smaller rim, but then you have to line up the disc etc. i did once see an XBR fitted with ( I think) Honda CB350 wheels to get the wire wheel/ TLS drum brake look on a cafe racer - he'd made a very nice job of it, but it wasn't easy. There was a guy a while ago somewhere on the forum who had converted the Comstars to wire using some turned alloy adaptor rings, again not an easy job.