Das Dresden Files RPG hat "Hulking Size", was vom Prinzip her genau das abdeckt. Wobei das vermutlich auch nur in einem gewissen Rahmen gilt, wenn ein Mensch nicht mehr ist als ein Käfer im Vergleich zum entsprechenden Wesen, dann wird man vermutlich mehr brauchen.
Hulking Size [–2]
Description: You’re very large, or able to become
very large at will if you’re a shapeshifter—at the
very largest, as tall as a house.
Note: This ability is always in effect unless you
can shapeshift.
Skills Affected: Fists, Weapons, Stealth, others.
Effects:
Easy to Hit, Hard to Hurt. You’re a pretty big
target, giving any attacker a +1 to hit you
when target size is a factor. But that increase
in body mass means you can soak up more
punishment, adding two boxes to the length
of your physical stress track.
Everything is Small. You cannot meaningfully
interact with any man-sized objects using
skills like Burglary and Craftsmanship (but
knowledge-related rolls are unaffected), and
you’ll have trouble fitting through normal
doorways and into rooms (this will confer an
automatic border value of 1 when changing
zones as appropriate). But it also means you
get a +2 to your Might rolls to lift or break
things—on top of any supernatural Strength
bonuses you might have—and a +1 on
Athletics rolls to cover distance with your
gigantic stride.
Big is Scary. You get +2 on any Intimidation
attempt against a target likely to consider
your size an advantage.
Easy to Detect. Your Stealth is automatically
considered to be Mediocre, and you may never
gain more than one shift on a Stealth roll.