I'll second the SL Keymate. For the size & price, it's a great light with an amazing amount of light for such a small package. Still, I'll probably use my Ultra G more simply because I can feed it used batteries from other devices. For my use, though, it's not a keychain-sized light.
Another possibility you might want to consider is a Coast Fisherman's Mini Flex Light (model FT7578CP). It puts out about the same amount of light that the Keymate does, but in a nice, diffuse beam with no hotspot. From about 6-8 ft, the beam is about 4 ft in diameter. It's the most uniform beam I have, except for my Surefires.