I wasn't clear when I said "create new units".
What I ment was, as you said, the USMC does tends to in fact create something like an "MRAP Company" and dole then out as needed.
Whereas the US Army tends to incorporate stuff into the existing MTOE thus essentially creating a new MTOE, thus "unit" type.
I'd heard about the fanciful notion to replace the all armored HMMWVs with MRAPs, and knew it'd been essentially stillborn.
What exactly do you have on M-ATV deployment, numbers, and incorporation, in the USMC?