If anyone can become an epic level character, I really don't see the point. Plus, as a DM, I am too lazy to do gaming sessions for a bunch of epic-levels PCs. Thus, in my setting players are not supposed to go beyond 20th level, and I will stop the campaign (due to boredom) well before that anyway. However, there is a couple of archetypal epic level spellcasters in my campaign, two of which are known (the "Master of the Fallen Tower" and a Galadriel-like enchantress). First thing, all of them are extremely old, several millenaries old in fact for the Galadriel-like elf. Personally I can well agree with a 50th level wizard 3000 years old, but not a 50th level PC in his twenties (looks totally ridiculous, despite this is fantasy and game).
That being said, the epic-level system appears to me as totally flawed and inept, plus really too time consuming to deal with, for a "lazy DM". So, I chose (from the SRD, I didn't and don't want to buy Epic Level Handbook) a few epic level spells that did look appropriate and houseruled they were in fact "True Rituals". Exit those ridiculous Spellcraft ranks needs (some spell requires 312 ranks in Spellcraft, for effects that are not that powerful), and exit those ridiculous millions of gold pieces and XP costs. Now, casting the spell is much longer than casting a normal spell, and requires to succeed a Spellcraft check which is reasonable. However, I didn't create special game mechanics, and forget about any playtest, the PCs have yet to encounter these epic-level npcs and have them cast such spells...