I own several Mega Bars and Mega Bar 50s (not the RC versions). I use the Mega Bars to up-light the wall behind my band and they work great. They put out a LOT of light and in any color you choose. I set them several feet apart and because they are just adding accents to the scene, I don't have worry about the less lit areas between the lights.
If, however, you are backlighting photographs and need a smooth, uniform color behind your image, I'm not sure you will be happy with these lights. They are less than 4' long and there is noticeably less light at the edges than across the middle of the bar. Also, there will be more light at the bottom of the back drop than at the top. Take a look at the lower left image on this page. If that kind of effect will work for you, these are great lights.
http://www.americandj.com/Prod...nId=2&Category=L.E.D.
The Mega Bar 50 will give you twice as many "stripes" up the wall.
Sadly, I'm not aware of any better lighting solution for your situation. If you don't need as much light as the Mega Bar you could save a little money with a Mega Pixel Bar, but you would give up the remote control feature and would likely want to get a controller.