I happened to have some extremely inexpensive LED strip lighting and decided to try a DIY LED moonlight bar. It works, maybe too well? Can too much blue light at night be bad? Aesthetically, its amazing! This pic was taken in the dark, and the colors are accurate:
If it isn't good for tank inhabitants, I can easily remove lighting strips. This was done with about $10 worth of LED strips and a 1 amp 12vDC wall wart.