Are there computer monitors that don't use backlight technology?

PixelQi makes displays that can both be backlit and work with ambient light.

I don't know if such computer monitors are availableyet. I do know that electronic paper works like this.

Impulse make transflective monitors: http://www.impulse-corp.co.uk/touchscreen-lcd-monitors/transflective-lcd-monitors/

There's a handful of similar manufacturers but they're nearly all professional, industry-specific stuff. Either outdoor display / advertising, medical, military etc. And they'll also have pricetags to accompany...

OLED would be the next logical jump, but the per-inch cost is still massive and it'll probably be usurped by LED-backlit for consumer goods. Perhaps you could investigate the few remaining SED manufacturers...