Remember one point. I had mine turned a number of years ago because it had gotten warped...something about difference in heat disipation between the original chome plating and the cast iron the chrome was plated onto... and since then, I have wished I had just bought a whole new one instead. Reason being that when the disk gets turned, there is naturally a certain amount of material lost, it ends up thinner. The brake caliper, and the thickness of the brake pads, is calculated with the thickness of the original disk in mind, not with the thickness of a turned disk. The pads now will stick further out of the caliper as they have further from the original specs to go to get to the rotor and make contact. The pads are then loose, and no longer have a tight fit in the caliper. They literally get "cocked" in the hole they sit in. They will make a clack, clack when the brakes are not being activated and you roll the bike forward. You will have to replace the pads much more often than normal, because the point where the steel pad backing starts to get close to looking out of the caliper will happen much faster, much less mileage will be gotten out of a pair of pads. and the looseness of the pads in the caliper will gradually enlarge the place they sit in the caliper...which makes them clack more. Visicious circle.
Bottom line. You make the caliper wear out quickly. You get noisy brakes that come on with a clack and a lurch and you buy pads twice as often as you would if you had just bought a new rotor and painted the center to your own taste. I have ridden with a turned rotor now for a while, and when I get a bit of cash, it will be one of things I replace. If you want your dreambike, invest in a new rotor, rather than turning down an old one. More bang for your buck.