Never knew of such USB powered monitor till yesterday.. 
 
There are a few brands, but the AOC is the most affordable ones , with 2 options, HD 1366x768 (E1659FWU) and full HD 1920x1080 (E1659FWUX Pro). ..there is another 17" HD too.
 
With no additional AC power / brick, this seems suitable for portable use, especially when used with Intel NUC / Gigabyte Brix / etc. I've read you can daisy chain USB for up to 6 monitors.

The problem with 1366x768 is some apps are not scalable and will run off the bottom of the screen.  I have that problem with Amplitube.

kitekrazy1
The problem with 1366x768 is some apps are not scalable and will run off the bottom of the screen.  I have that problem with Amplitube.

I've just bought one. Yes, while 1366x768 may appears larger in text for 16" screen, some apps will not fit in. At this resolution, it's good for my eye sight and BFD3 stand alone fits almost the entire screen.
 
Since it's a USB monitor, it only shows after Windows is fully booted up. You may assign this as a main monitor and shut down the main monitor to go portable.