I'm just playing around with builds but I'd like a Cleric who is incredibly versatile with his spells, such that he can generally cast almost any spell from any class list, should he choose to.
So far I've got:
Cloistered Cleric 5/Dweomerkeeper 10/Shadowcraft Mage 5
Required domains are Magic and Shadow. He uses the Domain Substitution spell to turn his Knowledge Domain into the Spell domain, so he's your standard Dweomercheater. That grants him a nice little mantle of spells that he can draw upon. He uses Shadowcraft Mage levels to emulate Evocation, Conjuration (Creation), and Conjuration (Summoning) Sor/Wiz spells.
He takes Customize Domain at first level, applying it to his Magic domain. This lets him select any spell of level-1 to fit each spell slot (Ie he could make Magic Missile his 2nd level spell choice, or Antimagic Field his 7th). Using this technique, he can get any spell but 9th level spells added to his list, should he choose. If he needs a different spell, he uses Supernatural Spell (Limited Wish) to get himself Psychic Reformation, where he picks all his spells again.
What other tricks can we apply to this character to get him casting more spells from other classes?
Incidentally, customize domain lets you pick ANY spell with the [Earth] descriptor for the Earth Domain, and same with the Air and Fire domains. Is there any way of getting every spell you cast to have the Earth or Air descriptor?