I think Sony made some kind of portable DVD recorder once with AV input and everything. Though I'm not sure how well it'd work being portable (may not be battery operated, may not handle bumps and all too well) As for hard drive units, there are some little DIVX players and such. Some might record, but again, probably no battery packs with them.
For the money you'd spend to do something like this, you could probably get something like the camcorder I just purchased (Aiptek ActionHD GVS, $180). Quality is actually very good, and could easily record at SD quality.
__________________
Primary- i7 920 | 6GB RAM | 9800GT | 160+160+500GB
Secondary- Athlon X2 4200 | 2GB RAM | 7600GT | 80+250GB
Netbook - Atom N280 | 2GB RAM | GMA945| 160GB
|