I got my fiber optics from The Fiber Optic Store: www.thefiberopticstore.com
High quality and lots of choices. You can even get "packages" on eBay.
Not necessarily a complete kit (you need to supply a small light source, like LEDs), but great stuff for models. These guys might be a lot of help: http://www.fiberopticproducts.com/Models.htm
If you're like me and want to do it yourself, here are some fantastic sources for LED lighting...
http://www.starshipmodeler.com/tech/cj_blink.htm
http://led.linear1.org/led.wiz
http://www.theledlight.com/ledcircuits.html