How about a manned ack that can be towed by a Jeep or an M-3.  The idea struck me last night as I was defending against the Nits who were rolling bases largly unopposed.
I figure it would be particularly useful in Vbase defense when all the hangers and ack are down.  It would give you a gun that could be spawned in and quicky brought to the field.  Kills and deaths would count as GV.