You can use the ways of gaining skill ranks beyond your level to qualify for Epic Spellcasting pre-epic. For instance, be Old or older and add the dragon type to any of the following, whether through Dragonwrought, half-dragon, or Polymorph/Metamorphosis/PAO/Shapechange; then, do the following:
An illithid savant can consume a creature with 24+ ranks in Spellcraft. Summoning and calling are good for this, as you can ensure the creature won't resist.
The Cityscape feat Primary Contact grants +1 skill rank above and beyond your level cap.
Bloodlines increase your skill cap without increasing your HD.
Using PsyRef and temporary HD (such as from Inspire Greatness) can boost your skill ranks permanently above your level.
Using Fusion on a high HD creature and using PsyRef, or hitting yourself with Astral Seed to make the effect permanent.
Hit yourself with multiple strains of lycanthropy until you break the level cap, take Epic Spellcasting, cast the spells you want, and cure the lycanthropy. Even better with the Curse of Lycanthropy spell. If you want the epic change to be permanent, use a thought bottle before you cure yourself, or use the negative levels/Greater Restoration trick to instantaneously retrain your lycanthropy "levels" to actual class levels.
Use the dusk giant's or barghest's ability to absorb Hit Dice.
Ally yourself with a void disciple with the Moment of Clarity ability.
There're a few 3rd party feats that let you break skill rank caps, including a few semi-official campaign settings that are sanctioned by WotC. I don't recall off the top of my head what those are, though.