Let the hive mind of Engadget get that for you.
"As someone who doesn't reside in the USA, I was wondering what would be the best way to get internet for my computer in the US for a couple of weeks? If it were Europe I know I'd look for some prepaid data. Is there anything similar offered by American carriers? A MiFi or a data SIM that I can tether from would work, but I'm trying to maintain a tight budget. Help!"
"Presumably battery powered (who would want a cable hanging off the wall?)"
How many of the HDTVs hanging on walls are battery powered?
I do seem to remember a some years back a printer targeted toward laptops that was just a bit wider than a sheet of paper was only thick enough for the print head and the ink and it was battery powered. There was no facility to feed more than one page at a time through it and nothing to catch it printed page. But it was touted as being small enough to slip into your laptop bag. A quick search of Google seems to indicate that it has gone the way of the Woolly Mammoth.