Howdy Murph'!
Man, with a real name like "Murphy Mc Craken", why do you even bother with any other call sign?
I mean, Murphy Mc Craken is a
cool name!
Anyway. I am loving your HRCT build up sir. And I must confess up front to being just a
tad self-indulgent with my praise.

Your wonderful HEMTT based build-up reminds me of my T2K '03 entry. A HEMTT based gun platform named 'Elvis'. She was originally named the 'War Wagon' (after one of my favourite John Wayne flicks), but the crew manning the vehicle just felt the name '
Elvis fit best....you know....the 'King' of the road and all....
The points brought up by matt, and concurred on by animal were very strong design issues I had to wrestle with when I was building 'Elvis'. In fact it was even more important in my case because I converted the normal eight-wheeled, 10-Ton version of the Italeri HEMTT kit, into the upgraded, ten-wheeled, 16-Ton PLS-based version. None of my additional improvements fell below the wheel centerline. That is, except for the protection around the front set of wheels, and that is made of a flexible, segmented curtain of Kevlar draped down to barely below that same centerline.
Since I have a new digital camera (for Father's Day), I just need to get a bit more familiar with it and I will post pics. I do have a few old pics that might suffice for now if you are interested...
Another thing. While I was brain-bashing about 'Elvis', I also thought about rerouting the exhaust. Not because of heat signature (good thinking), but more for discharge of diesel smoke which I felt was a very telling signature. The original plan I had was to reroute the exhaust downwards towards the undercarriage and vent, through a louvered system, just in front of the rear set of tyre's. I felt this would both outwardly reduce the evidence of smoke (by mixing with the disturbed dust caused by the tyre's, but also limit the vehicle's heat signature by spreading it onto an already heated surface (the road).
Maybe that same kind of thinking can be of help to you.
Additionally (I'm sure you've already thought of this), with
all of the computer's, electronics, personnel, etc. You are
definitely going to have to think about your deadliest foe......heat. Meaning, the standard design of the HEMTT truck has the massive engine located at the same level as the driver/co-driver, and the (potential) passengers. It will also (in your design), be located directly in front of, or more importantly, directly
upwind of all of these computers/electronics. Soooo, my compadre. Aside from having this design concern, you have also completely enclosed the engine within the (from appearance's) same outside skin as the C&C/Personnel compartment.
Now, I'm not saying all of this (and taking the time to type it all, since I'm a very slow typist) to throw 'wrench's' at you......no, no, no. I am doing my very best to assist you in any way I can.
Tread.