Wow. Those "Guppies" are sold at MEC in Canada (as "Turtles") for $3 or $5, can't remember. And they have a few models with more LEDs, and clip-ons (for running or for your pet).

They also sell a helmet-adapter for them.

Click here for all of MEC's bike lights:
http://www.mec.ca/Products/product_l...=1258950601366