I've got an HP one that supposedly uses a standard battery and works with Mac. I don't have the cable (it uses a big Centronics style printer plug) so I haven't bothered looking for the batteries. It does print a nice test page when you push the right buttons... Can't remember the model number off-hand, but it's definitely a HP DeskJet something or other. It's quite hot... It'd be incredibly Batman to get it working with, say, a Duo... or maybe my IBM Butterfly... Hmm!

I remember searching eBay for the Centronics printer -> Mac serial cable and seeing a bunch of them there for not-much, though obviously without the cable...