New-ish versions of Firefox (I'm currently on 3.6) have the nifty "search bookmark" feature, which allows you to create searches in the location bar with custom URLs, e.g. en.wikipedia.org/wiki/%s.
This is really great, but when trying to mange the engines in the search bar, I was dismayed at the lack of customisability there. It looks like the two search methods are entirely distinct.
Is there a way to put custom URLs in my search bar, or do I have to just hope that whatever I want is on the long but finite list of plugins at mycroft?
UPDATE: done a bit more research, posting my own answer