Well, what I'd like to do is Wis-drain an elder brain into a coma (Reducing its will save), hold out until all of its various buffs run out, then slap it with some Geas, domination, etc. The revolution begins when the Illithid civil war starts.
If it turns out that its totally immune to mind control and not just under some mind-blank effect, then we kill it, raise it as undead, and let Orcus worry about it.
There's got to be a animate dead spell somewhere that lets them keep racial features, SLAs, etc. I seriously considered running a dread necromancer, but it was easier to get Int to saves without losing caster levels than it was to get Cha to saves. And I don't know my necromancy and conjuration nearly as well as I know my illusion and enchantment.