Sounds interesting, I know in morrowind (referencing it again

) all those books and skeletons in game made me wish you could do something similiar - in fact I think there is a mod that allows you to do that!.
Anyway back to planeshift... I think it needs to be simplified a bit, make it more of a generic process to begin with. Perhaps separate to getting more powerful undead who could be better summoned and controlled that way (you rip them from somewhere else, the results could be interesting if you are weakened or they more powerful).
Having only read the first post I no doubt are repeating some of the posts that followed, anyway :
1. you need the bones of a creature (named bones) or a body.
(requires skill maybe? better the skill more knowledge more bones? )
2. you need a spell to animate the bones or body.
(maybe a preserving component if it has flesh?)
3. success comes from your successful cast of the spell modified by the creature to be animated.
(simplist thing I could thing off, solely success relies on the magic spell)
4. creature stats are standard to the creature, maybe resistance and vunerability if bones (eg. takes more damage if hit with a blunt smashing weapon.. depends on combat? no idea)
(base it off the original creature may save time depending on what is possible to be brought back)
5. the mana you are instilling in the creature sustains the flesh creating a limit on undead numbers.
(also saves hassle to do with decay, modeling etc)
6. possibily to help provide a limit to undead armies, the more creatures you control the more unstable the casting of the spell.
(success becoming harder as you are already maintaining another of the same spell? I just don\'t want to have dozens of skeletons to be rendered on my screen thats all).
7. undead behaviour, simpler is best. Treat these lowly constructs as expendable guards. Not sure on giving orders, maybe standard.... they follow and protect their master. Any repairs on undead are done by the player using more bones or whathave you (bonedust putty

) ).
Not sure but I think that may be simplier a bit, there is probably a better method then I suggest.
However it touches on something I wold like to see, artificing. Perhaps it would be more worthwhile if some generic ideas were used that allowed anything to be made? other contructs and clockwork machines resulting from some basic rules... unlikely but I can wish

.