This LED strip light housing looks as good turned off as turned on. The units are stackable in 150mm length increments. There are different variants of the lens and base (with no ends, one end, or two ends capped) for creating whatever length strip light you need. Just screw or stick the base units down end-to-end, add your strip lights (up to 10mm wide) and wiring, and then snap the lens covers in place. There are small gaps in each section to accommodate your wiring.

Printing
I printed these in PLA with 0.2mm layers, no supports are needed. You can use almost any even slightly translucent filament. Note that the lenses print on end, and in pairs. This is because they can get wobbly printed on end, and the pair of lenses, with small bridges between them, are much more stable while printing. (Note that the first STL file with just a single lens id for viewing purposes only.)