[JoshTriplett]

That's a really interesting idea. You'd want a fast toggle for it, so that you could use it primarily for browsing semantic content that uses colors, but not always for photographs or videos that represent the real world (unless those photos or videos contained such semantic content). It's not ideal, but much like assistive devices that translate vision to other nerve impulses (http://www.nei.nih.gov/news/briefs/weihenmayer.asp), it could be useful as a learned adaptation.

That said, it would also make sense for diff software in particular (as one of the most prominent software uses of red and green right next to each other for semantic purposes) to have an easily adjusted option for a different color scheme for the very common case of red/green colorblindness.