Lights that run long with a low output is a common topic here at BLF. It's an area of interest for people like myself, sb56637, Aleister and many others.
You might enjoy one of the $3 lights that output around 20 to 30 lumens for 10 hours, like the Powerlight HX-G011. But it doesn't tail stand well. A light that tail stands will bounce the light from the ceiling, illuminating the room nicely. You might like a LED lantern as well.
:Someone said they got 10 hours off this little $3 AAA light at DX: the Super Bright 7-1
Check out these threads as well for more ideas: