I purchased some LED strips from http://www.radiantz.com/. I can't link directly to the product I purchased, but I can tell you they're called 'Flexible LED Array.' You can choose the size in multiples of 5 LEDs; I decided on 25. The whole assembly with the 'D' Tube and end caps is about 4 inches long. They come with adhesive backing, so you just peel and stick.
I wanted them to go on the plastic to the right and left of the seat, so I had to drill a tiny hole in the the fender to run the wires. I also had to use silicone in the end caps to seal the water out. I put some around the hole where the wires run as well. I forgot I was going to need some resistors to get them to blink, so right now they just come on and stay on... resistors should be in on Monday.