40 quid!? Clarkie made mine for me for a few quid but he seemed to mysteriously disappear.
The Clarion reconditioning route is quite a good way to go but I wanted hands free phone integration.
Just found my bit. It's by a company called PAC (Pacific Accessory Corporation) and it seems to be called SWI-JACK Universal Steering Wheel Control Interface. It apparently works with JVC, Alpine, Clarion and Kenwood and can be programmed to work with many different cars.
I bought it on the back of a review that I think I read on here but you should be able to Google it. I'll fit it soon!
All the ones on ebay that support wheel controls via resistance values will work, Ive fitted a 7" gps dvd player one that works with the wheel controls