Okay, I'm not sure if anyone else will find these useful but I guess they might, basically they're a couple of macros for searching the imdb and dictionary.com in the same way as the search button does for google.

In macros.cfg put:

imdb {
open(javascript:if(search = prompt('Search the IMDb for:')) { self.location='http://uk.imdb.com/Find?'; + escape(search); })
}

dictionary {
open(javascript:if(search = prompt('Search dictionary for:')) { self.location='http://www.dictionary.com/cgi-bin/dict.pl?term='; + escape(search); })
}

And in toolbars.cfg put:

imdb {
macros(imdb)
search2.bmp[0]
search1.bmp[0]
}
dictionary {
macros(dictionary)
search2.bmp[1]
search1.bmp[1]
}

I placed them just after the print button, but they could go anywhere really, you'll also need search1.bmp and search2.bmp which can be found here: http://www.dumdeedum.com/kmeleon/
I'm not sure if using a javascript prompt is the best way to get the effect (especially since the default value doesn't work) but it until a better way comes along it'll do

hmmm, the lines to go in the macros.cfg that start with open( should probably be all one line, where's a preview button when you need one...

well, once a global variable for the current contents of the URI field is available for scripting purposes, you'll be able to put search querys in there, i s'pose... or, theoretically (i haven't tried it) you could have a macro that toggles the value of the user_pref for the search URL used by the built-in search dialog...

just random ideas.