I can see several applications that would make this type of network incredibly useful.
Having the ability to distribute situational awareness video in real time would be awesome. This could be useful independently from internet connectivity and a tablet with a decent amount of storage could keep the video for later review. If it were within the budget, wouldn't a head's up display in the firefighters helmet of something built into the brim of a law enforcement officer's hat be pretty slick? The ability to Wifi locate any of your team could also be quite useful.
Perhaps more to the point are disasters like Katrina or 9/11, where the telecommunications network may be down for extended periods of time. This kind of backup network could very well be the difference between life and death. If enough of these radios could be dropped in place with solar and battery backup as entire area could be brought back online in a very short period of time. Year's ago there was mention of a completely independent group of license exempt wireless pros forming an instant adhoc network on the the upcoming anniversary of September 11th to drive this exact point home.
As a suggestion, you might want to look if the 4.9GHz band in available in your location. Among others, Motorola's Motomesh uses this band. It's clean, licensed for this use, and some Wifi adapters can be switched to work in that band, lowering the cost for equipment.
Certainly, challenges exist and need to be worked through but if the opportunity to experiment is presented, why not go for it?