Perhaps a Skill Trick allowing for a potion effect to last a round longer instead, then? I'd imagine that to be somewhat similar - if the other way around and magical in a sense.Food would make a sort of sense, but you can go so long without it not sure it'd be worth a feat.
Oh you, you fluffy ninja.Found it before you even editted. Ha
...now I won't be able to ever look at your avatar again without thinking of tanuki.