Here's is a good search engine for the Craigslist, key in Airstream then click on Actual Listings (Slow) - This will display actual listings only from searches that return results. NOTE:Please be patient. This search may take a long time as it has to perform the requested search for each location and return the results. This could take anywhere from 20 seconds to 5 minutes.
By its very nature, Craigslist won't ever really be able to shut down these "consolidating" type of search engines. They implement whatever measures they can to mimimize it, but to code the individual sites to be substantially more restrictive than they currently are, would cut off a large segment of the less sophisticated population that they seek to serve the most.