It's funny that this thread would get active just as someone was asking about the expansion of the GB franchise within the movie, which got me thinking about the third movie script.
I'm thinking it would be cool in a third movie, provided it retains the idea that the GBI staff has greatly expanded, if the logos go back to the original, but there are modifications denoting geography and specialization.
This would apply to uniforms only - vehicles would still maintain the original logo.
Imagine the main logo patch, with text banners or flourishes to reflect what franchise your based with - a Chinatown hall could incorporate a dragon, or something (I was just in San Fransisco, and the Chinatown firehall has a dragon wrapped around their badge), or even other cities could have unique hall patches. All of them would have the GB logo as a main feature, but something extra, specific to the team that wears it.
Then, since Dan's script saw there being different vehicles (like a rolling containment unit truck) and 100+ employees, once you expand that out across the continent, it'd be handy in the field to be able to tell who specialized in what.
Anyone rated in the sciences wear some sort of patch on the arm, just under the logo patch. Drivers wear another, etc. Heck, why not adopt rank as well. The four guys worked well, but what if two or three halls respond to a big call? Who calls the shots?
So, name patch over right chest, station patch on shoulder with expertise and rank patch underneath - hmm, maybe expertise and rank can be one.
Anyhow, just talking out loud. Gives me an idea for a contest too - I've got a copy of the Ibook novel I'd like to give away.