Actually, a good TO wizard will have epic spell capability at 20th level, either via SCM goodness or access to a mythal. Either way, a TO wizard will definitely have a mythal, and that means even if he does go personally, he's got a million and one action abuses built in. Furthermore, at least in the case of
my TO Ultimate Mage, not only does he have the above, but he has 20th level spell slots at CL 40, and access to Su Miracles, meaning every spell/power/maneuver in the game at will. As I mentioned before, even the trademark Hand of Death SDA can't autohose this dude, let alone a lowly Holy Word at CL NI. Access to divine magic means HP damage/death is out too. The various immunity spells means no energy damage, and taking on the half-force dragon template takes away one of the last types that most creatures aren't immune to. All of this can be done with spells, and legally within the rules.
Now for actions...assuming a familiar, a cohort, an animal companion, and up to what, CL sims, just from class features/spells/feats alone the Ultimate Mage has an entire army worth of extra actions. All those Sims are capable of
celerity interrupts, and also Craft Contingent Spell, let alone actual
contingency as well. And since they are an expendable resource, they most likely are commanded to have them keyed to the UM. Throw in Ice Assassin, a Clone or five, and a contingent mythal, cast at the time right after his went up, to trigger in the highly unlikely event he was caught. In the event he's interacting at all, his sim won't even be talking through its astral projection, but through a projected image of itself. If it believes it can handle the threat, it will dispatch the nuisance itself, without losing the PI if possible, and in person properly buffed as need be. Also, that Sim doesn't even need to be of him. Ever wanted a non-dispellable, non-banishable Pit Fiend? Or Solar? Get creative
Sim Tarrasque door guards, and one as a pet riding dog? Sure! Sim dragons as gargoyles on the extraplanar abodes? Why not! Sim of someone who put up a decent fight
and actually required your direct involvement? Definitely, and possibly a properly seeded and contingencied to hell Clone even, to insure obedience. There was a reason I said in the killing gods thread that a well prepared wizard, even nonepic, still stands a good chance against an epic wizard and even against a god. They are just that hard to touch when their defenses are in turtle mode.
Hopefully this puts things into perspective, and I invite any would-be mage-slayer to have a look at me, Joda, and TML's work on my Ultimate Mage thread (also, I owe a good deal of that build's inspiration to Doc Rock). If you can drop that, you can drop pretty much anything, IMO.