Alternative Source Spell is always fun
I've allowed one of my players to do the following
Totem Druid (tiger) 3 / F. Conj. Wizard 1 / Mystic Theurge 4 / Arcane Hierophant 10 / Mystic Theurge 2
Otherworldly
Practiced Spellcaster
Alternative Source Spell (MT qualifier)
Companion Spellbond
Natural Bond
Basically going for jack-of-all swiss-army knife
Totem Druid from DR335 is taken to maintain a decent combat form and on-par animal companion throughout the levels.
If starting at high levels you could have a wildshape amulet, shapechange, etc. anyways.
If you do buy into both Alternative Source Spell and Precocious Apprentice, you might be able to do something like
Wiz 1 / Clr|Drd 1 / Y / MT
Precocious Apprentice
Alternative Source Spell
Prepare an arcane or divine version of X spell in your 2nd level PA spell slot.
I've always enjoyed the simplicity of this build
Wizard 5 / Mindbender 1 / Ur-Priest 2 / Mystic Theurge 8 / Arcane X
If you throw in Alternative Source Spell here, you possibly could DMM your wizard spells if you decide to prep them as divine