well you dont want a mini-DV camera. mini-DV cameras use very small and use presice mechanisms to operate the camera, that is the last type of camera you want mounted on a bike. They are very delicate.
If you want a digital camcorder, go with a Digital 8. They use bigger internal parts, and they are also built on tried and reliable technology. But I still do not recommend using a digital camcorder on a bike. Both cameras will be subjected to "byte fallout" (when certain parts of a video pixelate in a horizontal rectangle)
If you are willing to go analog, get a $190, VHS-C camcorder from walmart, just throw it away when it breaks, or sell it on ebay. But if you want to edit the footage, your gonna need a capture device for the computer.