I got sick of replacing the expensive and short lived bulbs for our existing kitchen cabinet lighting. I decided to roll my own since i could do it much cheaper than the commercial options, get way more features, and a custom fit.
The base is just .5″ mdf cut into 2.5″ strips with 45deg cuts half way through the material ~3/8th from the edge. Then I removed the sharp inner corner to prevent tear out when inserting the the cover. I use the router to carve out a pocket in the back to house the wiring.
I used a Colored LED kit (http://amzn.to/27hfB0K) so i could setup custom warm or cool tones, and they will be great for parties, and holidays etc. They can be cut about every 2″ and the wiring just involves attaching all the same colored wire together.
The white plastic cover is an LED diffuser sheet i got from Tap Plastics (http://goo.gl/efWNWS) but anything thin should work. Since this very low heat even paper might be acceptable if you cant find a suitable plastic.