Monk 2/Barbarian 2/Sorcerer 1/[Full BAB] 1/Abjurant Champion 5/Swiftblade 9
Pick up Elusive Target, and also look to stack up some DR x/--. Doesn't have to be much, just about 10 or so. At this point, your defenses are as such:
First, they have to hit your AC, which should be non-trivial. Also, Wraithstrike is not particularly effective, because your Touch AC is non-trivial.
Next, they have to get past your 50% miss-chance'd concealment, which is not an Illusion, so most methods of countering it simply don't apply. They could easily also have to get past your Greater Mirror Image spell, which is easier to circumvent but a much stronger rebuke against melee types. This also prevents any kind of sneak attack from working.
If they actually hit you, then all benefits from Power Attack are null and void and their damage is further reduced by 10 or so. As a result, you're probably taking less than 20 damage per hit. Really big things might hit you for 30 damage.
If, at any point, they miss you, you probably get a free trip against them.
Also, you have a 50% miss chance against targeted effects, even if they're not attack rolls.
If, after all this, something really nasty actually manages to get to you, you've got Wings of Cover.
Also, Hide and Move Silently are class skills from early on and for most levels, nevermind the fact that you can just throw Invisibility down and possibly turn incorporeal.
You're also a caster with a solid caster level, so anything that doesn't have decent grapple mods can be tangled up with Evard's Black Tentacles if you please.
As such, you're big, nasty, invisible, practically unhittable, do fucktons of damage in reprisal, and even trip as a bonus.