Awesome idea! How about this:
Conscription Center facility
Cost: equal to the IPC value of the territory where it is placed.
A Conscription Center can be built in any non-island territory with an IPC value of 2 or more that does not have an Industrial Complex. The Conscription Center is destroyed if the territory is captured by an enemy power.
A Conscription Center can mobilize conscript units (attack 0, defense 1, move 0, cost $1). The number of conscripts that may be mobilized each turn is equal to the IPC value of the territory. A conscript unit consists of a gray chip placed under the Conscription Center piece. The maximum number of conscripts that a Conscription Center may have is equal to 2 times the IPC value of the territory. If an Industrial Complex is built in a territory that already has a Conscription Center, no more conscripts may be mobilized there.
So for example a Conscription Center in Poland or Rostov would cost $2 to build, plus another $4 to fill up over the next 2 turns. Those 4 hit soakers would cost a grand total of $6, or half as much as infantry but they only defend on a 1 and can’t attack or move.
You could probably use something like red Monopoly hotels as conscription centers.