My experience

[why]

First I installed a fake K2000 VGA resolution DVR just to see how it works with all the vibrations. Image quality was reasonably good, and, to my surprise, the camera worked for almost a year without any waterproofing. Rainwater would get into the lens, and the image would be cloudy for a day or two until the water would dry, but no other damage to the cam. It worked until I lost it in minor crash.
Sample video:

After the success of the first cam I also installed a 720p K2000, waterproofing the board with a liquid electrical tape, the lens with a glued in neutral photo filter and wrapping the camera in electrical tape. Works so far.

Sample:

My bike with both cameras:

 

[alexanderfitu]

I like your idea. How did you waterproof the board?

How did you deal with the sd card slot etc, does that all still work?

 

[why]

Something similar to this http://www.amazon.com/Star-brite-Liquid-Electrical-Tape/dp/B0000AXNOD for waterproofing the board.
I covered the SD card slot with a flap of electrical tape. I also sprayed silicone grease in the card and power slots. This setup still works- almost a year by now. K2000 is only $40-45, a year of work would be good enough.

 

[DashCams Direct]

Hi, thanks for the share. Just wondering what powers that camera?

 

[why]

Camera is powered by a waterproof 12V to 5V DC-Dc converter I got on ebay.