Could you guys get some daylight readable transflective displays? NTSC or RGB?
Something like the NEC NL2432HC22 (QVGA) would be good for starters.
I think cholesteric LCD displays might also make a good SparkFun product. They’re a nifty technology but hard to buy.
The interesting thing about them is that they’ll keep their image if the power is removed (kind of like the e-ink displays that are starting to show up here and there). They’re also reflectively illuminated so they’re easily readable in bright light (not so much in dim light though)
Here’s one place that makes and sells them: http://www.kentdisplays.com/product/modules.htm I have no idea if they’re priced low enough to be worth it though.