I’ve updated an obsolete WordPress plugin called Sphider to be functional again. It wasn’t very much work, but the plugin code is far from ideal. That being said, it works, and Sphider is a pretty neat PHP search script. If you can get past the iframed UI, I believe it could be a solution for those looking for an alternative to WordPress’ default search.
Updated Code: https://github.com/chasecrawford/sphider-for-wordpress
If you have any problems with my updated version, please leave a comment.