There was one of the guys at SFO '12 that had covers for his. They were neoprene covers and looked very cool.
They just stretched over portion of the side cases. Very simple!
I can't remember who it was.
I'd be interested in finding something like these. I've seen a picture but didn't stash away a source. These covered the edges of the bags, where the two halves fit together, but left the center of the lids visible.
My left bag was rashed pretty well previously when it fell off the bike (wasn't locked down); right bag is dinged from a drop or low speed lowside. I don't need them to look new, just not be conversation starters