That certainly kicks the price up a bit. And would probably be more difficult to control from an Arduino.
I might do some testing with the LED strips as it's cheap, and see if it's aesthetically worthwhile and go from there.
macegr:
LED strips are probably not able to light up a canvas evenly, or at all beyond the edges. You need something more like an RGB PAR can or two, aimed at the canvas from above and back. Or an RGB wall-washer, aimed at the canvas from the floor. They can be found on eBay or American DJ pretty easily.