I bought one from Eastern Europe on eBay at a relatively good price. It was and is in mint condition. The EdMika brass adapter is not cheap but makes conversion very straightforward for those of us with less mechanical skills (he supplies a 2nd ball bearing for good reason - don't ask me how I know).
CameraServiceOne.com in the UK also convert this lens to EOS
I love the lens and haven't used it enough but will do so more in the future (too many lenses, too little time).