'Tis why I got chest-cam. Having video evidence might have helped secure a criminal prosecution of the guy who intentionally took me out Dec 2009.

once some cockhead realises he has been nabbed might then lay the slipper in & take off with the camera to get rid of any evidence

That could happen. More often people pull their heads in the experience seems to be.

It provides me with other benefits best discussed away from public forums

Any recommendations for cameras? The go pro is the only one i have heard of

A lot of the motorcycle guys are using these type of cheapies from ebay

http://www.ebay.com.au/itm/HD-808-H-264-11-keychain-camera-Keyfob-Video-...

that record onto microSD cards, I've seen the output and the quality is good even on a race bike although the wind noise is an issue (I suspect that will effect any camera though). That was the first link I could find but I know you can get them for about half that price including a SD card. For $20 it's tempting just to have a go and see what the outcome is,

They're supposed to be pretty darn good. Wind noise issues can largely be resolved by supergluing a piece of microphone fluff over the hole in the case.

Main issue for commuting use is the absence of water resistance. I'm currently looking for a lower res (say 720p) rear-mounted option.

Great thread on cameras here:
http://www.bicycles.net.au/forums/viewtopic.php?f=12&t=37405

FAQ here:
http://www.bicycles.net.au/forums/viewtopic.php?f=27&t=47178

Mounting FAQ here:
http://www.bicycles.net.au/forums/viewtopic.php?f=27&t=47412

Check Techmoan's Youtube channel for some impartial and thorough reviews on DVR micro and mini cameras.