Don't be surprised if you get no answer for your Firefox extension thread, it's impossible to add any comment because your have a second submit button in your post that has the same name than the submit button to add a comment (name='submit').
So, in answer to you post, here is what I wanted to add:
I made a few custom search engines that are added to the list in the search dropdown box. They're easy enough to make. I can make one that would search the Forums and one that would search the Gallery.