Hi

Don't forget Legions of Sentinels - a Beguiler Illusion spell that creates a mob of fighters, granting flanking for the party.

Then there's Advanced learning, where Beguilers can add Enchantment or Illusion spells to their list of spells known.

I mentioned Nightmare Spinner not only for their specal abilities, but the extra slots for Illusion spells. (And they're already an Int based spont caster)!

Cheers
Paul H