So, I was reading through Frank & K's Tomes and noticed two feats.
Fiend Cabalist
You were trained in the mystic arts by a powerful fiend, and your magical power stems from a dark source.
Prerequisites: Caster level 1
Benefit: You gain Knowledge (The Planes) as a class skill, all of your spells gain the [Evil] subtype, and spells you cast and magic items you create radiate an evil aura equal to the strength of their normal magical aura. Any spells you cast that already have the Evil subtype gain a +4 caster level.
Special: This feat can only be taken at 1st level.
Child Necromancer [General]
Prerequisites: Caster Level 1+, Must know at least one necromancy spell of each level you can cast
Benefit:Special: This feat can only be taken at 1st level. If circumstances ever cause a character to no longer meet the prerequisites of this feat, they may choose any metamagic feat they qualify for to permanently replace this feat.
I realised that there are a number of Necromancy spells with the [Evil] descriptor. So...
Ghoul strongheart halfling Dread necromancer 8/Ur-priest 2/Mystic theurge 10
Feats: Child Necromancer, Fiend Cabalist, Practiced Spellcaster (dread necromancer), Spell Focus (evil)
9th-level arcane and divine casting with up to CL 29 on both sides, and permanently Tiny. Any suggestions on improvements to the build? Take Attune Domain a few times, or A Feast Unknown->Devil Preparation? Or head into Divine Metamagic?