I recently watched Simulator Adventure's youtube video on a fire fighting plane: many people in the comments were discussing the posibility of fire engines in beamng, I think the T or MD series would be a good base for a more modern fire engine while the bruckell nine could have a config for an old fire engine. we have police cars and ambulances so it seems only fair that the third emergancy service should be included.
I just realised the Autobello Stambecoo has a firetruck config, something I overlooked but it would be cool if it had some fire fighting ability with water.