Hi Chris, feel free to browse my site, http://strikethebox.com, there are over 5,000 firefighting related tattoos on the site all inked on firefighters from over 15 different countries. If there is a specific design you are looking and can't find it on the site, let me know and I'll try to locate it for you.
Have you given any thought about what artist you would like to have ink it for you? That's almost as important as the design you choose, remember you're going to have this thing for life. : )