totally random selection:
2.5", 12V@90mA = 1W
3.5", 12V@350mA = 4.2W
6.2", 12V@650mA = 7.8W
This was all from one page, no search was done for "low power" screens.
Housed LCD Monitors from 2.5" to 15.4".
I will keep searching for small cameras for wattage. It is looking pretty good, so far.