I borrowed a printer from the GIS crew on Friday. It's a Pentax PocketJet 3 Plus, a diminutive portable printer for road warriors. It does 300 dpi black & white, and supports USB, iRDA, and Bluetooth. It'll run entirely on batteries (Pentax claims up to 100 pages per charge) and uses thermal paper. Yes, this means you need special paper, but Pentax's thermal paper is pretty good -- no curling -- and less per-page (15 cents/sheet) than comparable portable ink-jet printers (my GIS counterpart looked at a Cannon that worked out to 17 cents/page when to added up paper and ink). The best news is that, because it's a thermal printer instead of an ink-jet, the printouts are waterproof, the printer is smaller, and has fewer moving parts. Print quality is on a par with HP's vintage warhorse -- the DeskJet 500. The bad news is that it's not cheap -- $480 - $500 for the complete kit. But it is really, really cool.
As you can see, it really is small. Running on batteries and connected via Bluetooth or iRDA you could be printing in the field with no wires. I'm thinking that this might be a dandy tool for ashacat the next time she's off galavanting to India.