HoboGod
First Post
I think you are making things much more complicated than they really are. You never need to worry about Summon Monster X and Animate Dead stacking, because they are different effects (one summons a monster(s), the other allows you to control a specific amount of undead).
I'm sorry, I wasn't clear. I mean to say Summon Monster stacking with itself, not to question if it could stack with Animate Dead. That is, to cast Summon Monster I twice to summon two monsters at once. I'm using Summon Monster I to question how stacking works if stacking only occurs where stacking rules suggests. By understanding this, we may understand haw Animate Dead works.
Likewise, there are no issues if a different character casts Animate Dead. Stacking of these effects is based on "you", i.e the caster. You are never limited in the amount of HD of undead you can control because of another character casting the spell.
It doesn't say that by RAW, though! If it did, there'd be less hubbub about it. The rules make no blanket statement like "aspects of spells stack when and only when...." Because of this, a spell like Animate Dead is a headache because it works like other spells, each interpreted differently, some can stack, some don't stack, some only slightly stack.