Can't become a zombie, I'm already a lich. . . I'll look into Races of the Dragon though, thanks.

If you have the Complete Arcane, you can take the feat Persistent spell and have a low level spell that gives you a natural attack last. A good one I know of is Fist of Stone.

Naw, I'm a cleric. Divine Metamagicing Persistent every day would burn up most of my turn attempts. . . though I suppose I could see if the DM is going to allow custom magic items, just get something like that.

Or just ask to treat your fist as a natural weapon. It's natural. It's as much a part of your body as a fang. If you've got Improved Unarmed Strike, you can use it as well as if it were a weapon. I think it'd be harder to justify it not counting as a natural weapon.

Okay, for some reason I had it in my head that Divine Metamagic was the only way to add metamagic to a divine spell, but that seems to be incorrect, yes? I haven't really played cleric much before.

That is incorrect, divine metamagic lets you lower the cost of a metamagic by burning turn attempts. Get the magic item that has charges of turn undead (night stick I believe) and/or extra turning and bam cheap metamagic buffs all day.

I am currently playing an undead True Necromancer. Is there any way to "switch" undead templates?
Ex. a way to turn a vampire into a lich

...wish, miracle, some kind of ressurection followed by the lich ritual. Thats about all I can think of.

Any magic items around that increase an existing flight speed?

Boots of Speed would increase the flight speed for short distances.