Ah yes, yet another DSLR accessory you can't pass up! except this time, probably its true.
This is a behind the lens, fits into the body filter that adds exactly enough diffusion to get rid of moire on the camera while keeping the image as sharp as possible. Its probably a must own for just under $400 if you can get one. Preorders here.
Its easy to insert in or remove so there is no permanent camera modification. I had honestly thought of doing something very similar, except for mounting the filter just in front of the shutter & imager. It would be a glue in place deal and permenent. I'm sure lots of folks had the same idea, but this guy who specializes in anti-aliasing filters for all sorts of electronic cameras really had the right super scientific materials to do the job.
This may well be the fix for now for current owners. No APS-C sensor filter yet. This filter is not recommended for lenses wider then 24mm on the 5D Nothing is perfect, but it sure makes a 5D much better. Hello canon get off your butts and give us proper video without problems !
Video Review on how to shoot extra small stuff.