Meta-Meta Search: Arbitraging the Arbitrageurs

News that Pricegrabber has added airfares to its price comparison engine got me thinking. The main reason for the recent emergence of all these meta-fare engines (Kayak, Mobissimo, Sidestep, etc.) is that Expedia et al., aren’t doing the best job of searching the fare universe. For example, they rely overly on “official” data directly from the airlines, so they miss the specials that airlines and aggregators offer directly on their own sites.
How long, however, can it be until there are meta-meta fare engines? Because now that there are four meta search engines most people won’t have time to check them all, but a quick persual shows they do come up with different fares for the same routes. There is an opportunity, ironically enough, to abritrage the arbitrageurs by searching the meta-search engines for the best route prices.