In Cycles you can add nodes to lights like a spotlight and thus project light "gobos" like in the attached screenshot. This is a good feature to have for creative lighting and should be separated from the materials on the object themselves. I have attached a screenshot of how it works in Cycles wich I find good. I have also attached a file/.blend from wich this screenshot was taken.
Is this something that can be easily added ? On the roadmap? Never?