Laborious Training [General]
Your selfless dedication to study and the long hours you have spent training for your craft have given you an increased capacity for learning. Prerequisites: Int 13, Knowledge (any one) 5 ranks.
Benefit: Your maximum rank in any Intelligence- based skill equals 5 + your character level. Normal: A character’s maximum rank in any skill equals 3 + character level.
From Ravenloft Legacy of the Blood pg 92
could this let you qualify for epic feats before being epic? or do you have to have 21+ levels?
You need to be epic, but dragons that are Old or older can ignore that. Insert Dragonwrought Kobold here.
A lot of epic feats need more than 24 or 25 ranks in a skill, though (and quite a few don't need epic skills at all, or need non-Int skills), so the amount potentially unlocked by adding this is fairly low:
Augmented Alchemy (Craft(alchemy) 24)
Automatic Silent Spell (Spellcraft 24)
Magical Beast Companion (Know(nature) 24)
Plant Wild Shape (Know(nature) 24)
Vermin Wild Shape (Know(nature) 24)
Efficient Item Creation (Know(arcana) 24, Spellcraft 24)
Epic Spellcasting (Know(arcana/religion/nature) 24, Spellcraft 24)
Ignore Material Components (Spellcraft 25)
Improved Combat Casting (Spellcraft 25)
Permanent Emanation (Spellcraft 25)
Scribe Epic Scroll (Know(arcana) 24, Spellcraft 24)
Spell Opportunity (Spellcraft 25)
Spell Stowaway (Spellcraft 24)
Spontaneous Spell (Spellcraft 25)
Ignore Material Components and Spell Stowaway are the really-interesting ones there (Epic Spellcasting's not great at subepic without gate-chaining or hiring a pile of NPC spellcasters, although this feat is useful for it later on since your epic slots/day is proportional to Knowledge ranks).