Thanks. That is more or less what I thought you might mean. Not sure if you are right though.
Incidentally, while looking for something else I stumbled on
this. So looks like it wouldn't actually be necessary to pick a search engine. We could just let Shareaza support adding torrent search engines the same way Firefox supports adding search engines. Or Shareaza supports adding ED2K servers. Still no idea if it would be useful, but it seems it would be doable.