These don't fit your 'non-backlit' requirement, but I know of a couple USB monitors:
Mimo 710
All four Mimo models
These aren't useful for everything, like video, since the bandwidth of USB 2.0 (480Mbps) is only sufficient for transferring non-compressed video with a resolution of 640x480 and a frame rate of 60Hz. Compressed video (Flash, H.264, etc.) may not have a problem though.