beedspeed do a bracket with a m/c (nissin) that bolts on and sip do a bracket to use the grimeca m/c both require some filing of the orginal headset -only thing is they throw the m/c lever a long way out
I upgraded my non disc PX about 6 months ago with a SCOOTRS kit and have not looked back. The headset was easy to modify with hack saw, file and dremmel. The thing I had in my favour was this was carried out before respraying so i didn't have to worry about damaging the paintwork. But the results are great, excellent braking with suprisingly good feedback and feel. It was just a bit of a pain to bleed at first.