Thanks for the links ricin, the camcorderinfo.com site has some good info, especially the graphical results of the OIS tests. It looks as though the Sony HDR-CX500V has the best OIS around at the moment (for consumer grade camcorders). Pity it is about $500 more than the Canon here
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The SmartyCam looks like a great solution for racing, especially if you have the sensor data available, but it is overkill for my usage of just driving along dirt tracks. Also I don't see any mention of image stabilisation although I assume it would have to have it in some form.