If the slits are just for looks and not to allow the enclosure to breath, AND
if you like BLUE/green, there's always electroluminescent strip lighting. Perhaps
you've seen them in those flat, flush nightlights? Very low current draw and run
directly off of 120 or 230V. By their nature, it's a uniform lighting and not harsh
to look at.
They do come in other colors. Can often get free samples from the various
manufacturers. Ones I got a few years back as samples were approximately
1 x 3" (and ~1/32" thick).
See
http://en.wikipedia.org/wiki/Electroluminescence for a brief
article on the stuff.
Dan