My views:
If you want major pose value then do as Stephen says and fit an HRC rotor, then CNC up the necessary bracket, anodize it a funky colour and cruise around showing it off at every opportunity. It is HRC after all. Don't forget to keep telling everyone that fact either. On a posistive side you'd be pretty sure it was gonna work.
Or, you could buy Andy's when it's fully tested. Looks rather fine to me, and I'm sure that it'll get it's weight in poser points, which won't be many then!
Those machined rotors look cool, but I'd like to try before I buy. I tested a bunch of 'modified' front rotors some time back and everyone warped like a Pringle with a bit of abuse cos they couldn't get rid of the heat.
Or, if you're a cheapskate like me who'd rather spend cash on tyres than bling then skim you're stock rotor to lighten it up. Won't get any cheers in the boozer but will do the job.
Finally though, if you're just into hooning around the streets, with the occasional track day then the stock rotor will do you fine. It stops, doesn't exactly weigh a ton, and I've seen far uglier.
In the UK back in the early '90's when I was wobbling round on an RS125 there were some guys trying aluminium, and also carbon rotors. Neither really worked for shite, but they got through scrotum-neering and that was about it. The carbon was actually supposed to make a noticeable difference to the handling, even for the average rider, but I never had the pleasure.
We could knock up a carbon rotor tomorrow, but there's no way I'd guarantee it for anything other than hanging on the wall. Might be good for a picture to post to Andy in a vain attempt at some extra poser points though.
Hmmm.