I suppose partisans could work something like this:
Cost: 4 IPCs
A max. of 1 can be recruited each turn. When recruited, can be placed on any enemy-conquered non-homeland territory (in AAE, this would be the grey areas belonging to germany but being conquered rather than mainland, with Italy being an exception). However, they can be moved to enemy homelands once recruited from conquered lands.
They work like ordinary infantry, with a few special rules:
They have two modes: Surfaced and hidden (symbolise by tipping over like battleships and subs). They can switch mode either during the combat or non-combat movement (depending on whether they come into combat or not). They can both surface, hide and move in the same turn.
When surfaced, they work like infantry in all respects, with the exception that when they defend they have the “disappear” ability, which works like subs submerging, with the exception that they can’t re-surface during the same battle. Each attacking infantry gets a sniffing out attempt (see later), and any surviving partisans become hidden in the region.
When hidden, partisans don’t interact in any way with the enemy: They can’t conquer territories, they can’t attack or be attacked, they move freely, and they can be in the same area as enemies without anything happening. They’re effectively ghosts, with two exceptions:
SNIFFING OUT: Enemy infantry units in the same region as a hidden partisan can attempt to sniff 'em out. This is done during the combat movement, and no other action can be taken by the sniffing infantry. The sniffing unit rolls one dice for each hidden partisan in the region. For each 1 scored, a partisan has been found, put against the wall and got his brains shot out while chanting his anthem.
SABOTAGING: A hidden partisan can attempt a sabotage in the region. All enemy infantry units get a sniff-out attempt against all saboteurs (e.g. if there are two enemy infantry in a region and three partisans attempt a sabotage, a total of 6 dice will be rolled). Any surviving partisans immediately destroy 1 IPC from the enemy. Unless there is a homeland industrial complex in the region, the maximun IPCs destroyed is the IPC value of the region.