HeavyArty
It would be interesting if the M7 Priest was still in use today. The 105mm gun hasn't changed that much, so who knows.
LoL--I just had a mental image of a gutted Brad with an M20A poking out . . .
We don't really have a modern equivalent to M3 and M4 chassis that isn't already an SPG.
Hmm, an M88 rigged like an Abbot, to shoot over its own tail, maybe? Spade would already be in the fight spot, just need a platform for ammo service to the gun
Mind, given the need for ammo supply, it would seem that a semi-trailer mount served by the same prime movers in the trains already would e logical. Maybe. Perhaps.
Or, gee, our already mature SPG inventory seems sufficient.
Dang it, talked myself out of what-ifs