There may indeed be some of the classic "campaign breakers" left, but many of them have been trimmed out of the ruleset already.
I'm pretty sure that save-or-dies are a viable way to go, and one of the few ways not already being attempted. Immense defenses are common (in other words, there are many near-maximal concepts running already and there will be some rock-paper-scissors effect), but in the end, you've got to be able to punch through one defense somehow. Gishes can do that with natural 20s and time. Gishes can also probably be crunched by a pure caster. I have a plan now, but I'm wondering whether I can do better with a second attempt.
So, is there any way to match or beat roughly +2 Cha/level for a large number of levels? (That's the bar set by the evolved template.) Or failing that, what's the highest Cha/LA entry into any undead class?