Shield Cover is an optional rule that Kromm introduced in 2013 at http://forums.sjgames.com/showpost.php?p=1692962&postcount=9
Optional Rule: Shield Cover[]
When using this rule, shields work as usual and gain one additional benefit: they provide cover to one hit location per point of DB, as well as to the shield arm and shield hand. Allowed locations for this purpose are the skull (including eyes and ears), face (including nose and jaw), neck, torso (including chest, abdomen, and groin), weapon arm, weapon hand, weapon, either leg, and either foot. If a location includes vitals, joints, veins/arteries, or other subcomponents, these are protected as well. The torso is the most effective choice, as it's far larger than the other locations yet easier to screen because it's central; holding a shield out to cover a foot, hand, weapon, etc. is less efficient.
The GM decides how much detail to use. By default, a DB 1 shield protects the torso, a DB 2 one covers the neck and torso, and a DB 3 one screens the neck, torso, and one leg. If the GM wishes, shield users may shift coverage to the same number of adjacent hit locations as a free action at the start of their turn; e.g., a fighter with a DB 3 shield could move it sideways to screen his weapon arm, weapon hand, and weapon, or downward over his torso and both legs, while a warrior with a DB 2 shield could raise it and peek around it, protecting his skull and face. This is an added complication, best-suited to groups who know the combat rules well.
Areas protected by the shield gain the usual effects of cover: an extra -2 to be hit. If a blow to a protected location misses by one or two, it will hit the shield instead. The defender may opt to let this happen or defend normally. If the shield is hit, its cover DR protects the location originally targeted and the shield suffers damage (if tracking shield HP).
Advanced Options[]
Extreme Coverage[]
Those with DB 2+ shields can opt to dedicate the shield to protecting fewer than the usual number of hit locations. Every location sacrificed grants an extra -1 to be hit on one protected location. For instance, a warrior with a DB 3 shield could focus on just the torso, making it -4 to be hit, or protect only the torso and neck, giving an extra -3 to hit one location and the usual -2 to hit the other. The range of misses that hit the shield is likewise expanded.
Skull Coverage[]
Realistically, covering the skull (and thus the eyes) limits vision. The GM may wish to give those peering around shields held high the same -2 to hit that their enemies have to hit their skull – because in effect, all their foes enjoy cover!
Weapon Coverage[]
A covered-up weapon is harder not just to hit, but also to use and see coming. Attacks with it are at -1, but enemies have -1 to defend against it.