I have an 80Gb Archos AV504 into which I plug in the Archos Helmet Camcorder.
The qualities way off what you'd get from a dedicated AV input to a camcorder, but decent enough and streets ahead of things like the Oregon and Tony Hawks which record to memory cards.
The only limiting factor with the Archos in terms of recording is battery life...mine will record for the whole length of time it takes a fully charged battery to drain - around 4.5 hours depending on the temperature. It will however run off a 12v feed whilst recording...though I've never done this.
Another benefit is it the 4.3" screen is very watchable and, as its basically just a hard drive with a screen, you can upload and store movies on there as well for those rainy evenings in your tent and all your mp3's too.
I also have the dock, which means I drop the unit in and can then watch anything I've recorded on the cam (or the films I've downloaded off t'internet) on my TV and control the whole thing with a remote. Oh and it has a timer too so you can use it instead of your video recorder to record the telly. It'll even record off DVDs and encrypted satellite channels...allegedly.
I'm quite chuffed with mine