I got a newsletter with this
http://www.guyotdesigns.com/site/img...ireflypage.gif
in it - It's called the Firefly and its an LED lid for a standard wide mouth bottle.
( http://www.guyotdesigns.com/firefly )
I'm thinking paired with something like this
http://media.rei.com/media/757629.jpg
and you'd have a similar effect that could be put in your water bottle cage for about $35 or less (though it would be on the wrong side of the downtube to shine on the ground as much)

