COMP00, yes the question has been asked, and the suggestion of tacking 5-10 appliances on the end of a Mets has been made. The response was "We are not, and never will be the MFS"
It would be smart thing to do, it would also mean that all servicing etc, could be carried out in Adelaide, rather than in the sticks, or interstate.
Mind you, half of those places you mention have no need for anything more than a Type 2, don't do enough work to justify the cash outlay, or will be eaten by SAMFS in the next 10 years.
If the CFS built decent appliances that could be used for multiple roles, there wouldn't be half the issues there are today.