It's an interesting and good idea. I have no experience with joomfish at present. I also do not have any language string translations for the plugin - there is only English at the moment. The blacklist cannot be placed in the language string due to Joomla limitations unfortunately. I would like to maintain a list of translations of the blacklist. There is also a problem currently with the parameters not displaying correctly if your admin backend is not set to English.
So, there's a lot to do before Joomfish support is realistic. Can you add it to the tracker?
joomlacode.org/gf/project/addkeywords/tracker/
