I got this one from someone I knew that hadn't used it. The same frame/handle (its 500mm) can be had from Demon Tweeks/Rally Design/OBP I think for about £50-60, then all you need is a cylinder (Wilwood .625 are about £30 on eBay). Can be done cheaper if you keep an eye out for a second hand setup or similar, Driftworks sell the whole lot as one ready to go but more ££