When I was in third grade, there was one for sale with full interior, running, 1:1 scale. If I only had $2000! LOL.
The M3A3 would be a great one for an interior, nice BIG hatches! I know AFV puts out a PE set for it, but I didn't use much of it on mine. It does have some nice grouser racks in case you want to mount the grousers on the tracks rather than the turret.
Ron