250mm front rotor on X hub

I got some X wheels for my 250R and want to put on a smaller 250mm rotor on the X hub so I don't have to change out the caliper every time I switch out the wheels. I've read of a guy in the UK that got a hold of a smaller rotor that bolts up to the bigger X hub. But where can I buy one in the states?

Just an FYI Forrest from Wheeling Supply hooked me up with a custom 250mm front rotor that bolts onto the X wheel so that you can retain the stock R front brake setup up. The rotor requires some filing to make it fit and taking some material off of the back of the caliper so that the rotor bolts don't rub. Forrest is extremely helpful and answered all my questions.