On a whim, a plugged a USB Host OTG into our Nexus 7 and attached my IOGear wireless keyboard and trackball to it. After furiously clicking the reset button on both the keyboard and USB dongle the most amazing thing happened, the keyboard Just Worked.
That's right, a little mouse pointer appeared on the screen when I moved the trackball and the keyboard, well, keyboarded.
I then installed Terminal IDE (no rooting needed) and suddenly I was in Linux-land. I could access files, use vim and generally do anything BusyBox would allow. Even a number of keyboard shortcuts worked, including Alt-Tab to switch among windows.
Of course, I wanted to do more. From my reading, I see that emacs should totally be possible (whoo!), but I've yet to try it. A little testing to get opkg and a number of additional Linux programs to run on the device was a flop (the instructions call for running wget over adb.exe shell, but that command isn't found), so I've still got work to do.
Apparently, if I'm feeling up to it, I can go as far as turning the Nexus 7 into a full blown Linux box. Two options I've found: (a) run Debian alongside Android or (b) boot up Ubuntu instead of Android on the device. (a) requires root access and (b) requires a factory reset, so both options are somewhat extreme. But still, good to know they are out there.
In the mean time, I'm weighing whether or not I should get a tiny bluetooth keyboard so that I can make the setup a whole lot more portable. I'm also wondering how much of this I can do on my Galaxy S3. If I had the right set of Unix tools on my cellphone and a keyboard to access them, there may be times I could get away with not bringing along my Netbook when I travel. I usually do this as an insurance policy in case I need to fix some broken code, but with vim, svn and a few other utilities I may be able to do that from my phone. One can dream, right?