[Lucid:]

The reason that rainbow is the color added as an extra color option in DIs is because it takes extra time to do and rainbows will never be included in commons. Because there will never be rainbow commons, we add the rainbows to DIs to give some options to those who want to create rainbow-based avatars. I know it can be frustrating that a particular item doesn't come in "your" color, but we can't make DIs in every color to appease every person.