I know people are always looking for smaller devices these days, so would a portable device with a screen less than square meet your needs? LOL! How’s that for a niche client!
Seriously these guys make OLED displays for fiberoptic applications. 0.5cm .
It sounds great and the resolution is fine, but I just think it would look sorta funny mounted on my vesa wall mount in the living room.
http://www.emagin.com/
