I was looking for 6mm wide LED strip. White LED was the goal, RGB if possible. I could have use the LCD backlight kit but I design my own strips with White and RGB LED. To fit both on the same strips, I used addressable RGB LED. The WS2812b were a very nice fit as they have a reduced pin count allowing white LED PCB routing. The full RGB colors is pretty nice. The integrated controller simplifies the control electronics. The brightness to power ratio is not as great as bright white LED.
The board is 10cm by 10cm and has 14 strips. Each strips fits 5 WS2812b and 4 White LED footprint (PLCC-2 SMD, each foot print can fit 2-3 LED). The WS2812b are powered in parallel and the White LED are powered in series. The strip can be chained to make a long RGB strip. I chain 6 strip per panel on my design. Two strips white LED can be chained to be powered from a 25.2V source instead of a 12.6V.
The strip has 2 mounting holes, drilled at 2mm. They can be drilled to 3mm.
I bought the White LED and WS2812b on ebay and soldered them myself.
I have left over 10x10 Strip PCB panel (No LED). I would sell for $10. PM me if interested.