I've created a block of each color of dyed wool for in-game reference and was looking around central Bridgeport for a good place to put them. I need a strip of 3x17 blocks long and it looks like the only place it would fit would be on the hill behind Bridgeport Heights.
Brad, mind if I put the spectrum-strip over there? I promise I won't make it look too out of place. 
[edit]: Scratch that. I'm going to put it in between the redstone testing grounds and the wheat/cane farm. I think it makes better sense there.