Fabfinder is a project mainly written in ..., it's free.
Extensible Joomla 1.7 admin search module
This system plugin and admin module allow you to search from within your Joomal1.7 administration pages. You can search for:
Search types can be added by adding a PHP file to plugins/system/fabfinder/adaptors/
They should set a variable $tmp which is then merged into the search results.
$tmp should be an array of objects, each object should have the following properties
generally $tmp is produced by a database query- see plugins/system/fabfinder/adaptors/content.php for an example.