I ordered an eBay "N800" battery from Hong Kong - and I was sent the wrong one. They said they'd send me the correct one after I sent them a .jpg comparison shot.
I also got an cheap car charger for the N800. It seems to charge intermittedly and is good only for plugging in and using directly when the battery is low.
I'm considering one of those emergency single AA battery chargers. I just bought the Energizer 2 AA Nokia phone charger, but seems less "pocketable"