Epic Spells
 

Hi so I was thinking since I already got all the leveling beyond 20 figured out, with the BAB and saves at least maybe I could start making feats and spells.
now the feats are mostly text but the real trouble here is spellcasting.

so my question is: is it possible to create a new tag for 10th level spells or am I gonna have to do something crazy here? in addition is it possible to add to a caster (through the epic spellcasting feat) a custom spacial ability (that way the spells can be like an extra ability like Domain or spacialization spells)?

Also I'm very open to any ideas you guys might have and ways to make it more efficient. :)