This may be a reach, but there are no stupid questions, right?

Has anybody heard of or seen an archive of search engines, and in particular their query string formats?

I maintain a statistics plugin for Wordpress that's quickly growing in popularity and certain aspects of it could wind up usurping all my time just trying to maintain current data. In that respect, I'm also looking for a good geolocation alternative to hostip.info (preferably one that doesn't go down every few days, for example).

If you're unsure of what I'm asking, one of the basic operations of the statistics aggregation is to determine if the current visitor came from a search engine, and if so, what search terms they used to arrive at your page. To this end I'm parsing the referrer and looking for known search engines based on a definitions list I maintain with the plugin. When a known engine is found, it then parses the query string for that particular engines 'q=' and determines what search terms were used based on that info.

I've got 56 engines defined, however I know that's a pretty dismal list compared to the probability of engines in use.