Inner Sea Taverns expands such thing. Pages 54 and 55 have rules for sober, tipsy, drunk, soused and passed out. To jump from one to another it's usually
Q76.If you consume an additional number of alcoholic drinks equal to your Constitution modifier (minimum 1) within an hour, or if you consume more than one alcoholic drink per hour for a number of hours equal to your Constitution modifier (minimum 1),
Rage Power Guarded Stance:
Is the Con+Modifier duration per rage or per day?Benefit: The barbarian gains a +1 dodge bonus to her Armor Class against melee attacks for a number of rounds equal to the barbarianís current Constitution modifier (minimum 1). This bonus increases by +1 for every 6 levels the barbarian has attained. Activating this ability is a move action that does not provoke an attack of opportunity.