I have a feeling this might be another "Paper Panzer" so to speak, but the General Service shelter box was certainly offered on the Maultier frame and the Ambulance shelter (lower roof overall but raised clesestory down the middle of the roof was also offered,) so this combination is definately possible.
If anyone feels nervous about this combo just move the ambulance shelter over onto a standard Blitz chassis and you are definately good to go!
p.s. The side storage boxes that fill the wheelweld cut-outs on the Maultier version are seperate castings in the kit so they can be easily left out on the straight Blitz. Also it is a toss up on needing rear fenders on the straight Blitz. Many had them when the shelter box was installed, many did not to save on sheet metal!