you didn't mention the overall size screen you are considering, though i imagine that it would be a 7" screen..
overall, the screen tech has not changed much since your last time here... the biggest difference is that the screens are brighter, some have usb-only connections, and they can be upgraded with a capacitive touch layer-- though, i am not aware of any 7" screens that come from the oem with a cap. touch layer.
overall, i do not recommend usb screens for single screen installs due to the fact that they will not display anything until after the os has loaded-- so any issues before the os loads would require a 'normal' monitor to connect and diagnose--which can be problematic if your a long ways from home..
many of the screens are still quite bulky, so i don't think that your goal is achievable with the current batch of lilliput/xenarc models(it ought to be something that should be possible by now, but it not ).
however, there are larger super-thin led back lit pc monitors in the 19-22" range that should fit the thickness requirement. many require 19v power, which can be accomplished with a carnetix or dc-dc-usb power supply.