I'm not sure it fits what he's talking about, but I've found book burro (http://www.bookburro.org/ http://www.bookburro.org/) quite helpful. It collects results

I'm not sure it fits what he's talking about, but I've found book burro (http://www.bookburro.org/ http://www.bookburro.org/) quite helpful. It collects results from several used book price searchers, rather than searching inside book content, but it can also search for library availability in a $distance radius, which is nice.