No. There is no mini extension like Chrome and Safari have, and I don't think one is planned; for obvious reasons it is a lower priority than creating an IE extension, or any of a great many important projects.
Still, it would probably be quite easy to create such an extension-- the Chrome and Safari extensions are quite simple, and the more powerful extension system in Firefox would make it a breeze.
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Still, it would probably be quite easy to create such an extension-- the Chrome and Safari extensions are quite simple, and the more powerful extension system in Firefox would make it a breeze.