Thanks for this thread, all! I really like how it hides all the stuff hanging off the back of the tank like the filter, cables, CO2 line with a white foamboard, and at the same time serves as a backdrop for light diffusion. Backlight is the old Aqueon CFL hood's full spectrum bulb, and now that the HOB is propped by the foamboard i could use the HOB's plastic offset dongle to offset the aqueon hood light from the back of the tank at any angle needed. Separate outlet from the LED so it could run even when the LED turned off due to the timer, and bingo - done! Here's the setup, and some examples of how it looks with the Current Freshwater LED plus - RGB madness!
Here's a Sunrise look, with a low light orange coming from the LED:
Here's a little moonrise:
Here's a Blair Witch Project look with the LED off and just the backlight on:
And here's my son's favorite, an Aqua look that makes it seem like the water is blue and the plants still pop green:
Total cost - 10 bucks for the foamboard, that's it!