I ripped the seige engine and turning for my house rules. I kicked 3e skills to the curb. However I have made some changes so they both work with 3e better. Since I have made changes to the mechanic, I now call the 3e tack on derived from the SEIGE engine the MOAT system.
Humans get three primes they can allocate whereever they want. Its not based on class in my house rules for 3e. Demihumans and all other races get two primes which they can use like the humans. Monsters that have a "as characters" entry get 2. Monsters that to not have a "as characters" entry get 3.
Class skills are noted on the sheet with the class abilities and for these the character gets to add their class level. If the character has more than one class, the character gets to add the class level appropriate to that skill. If the skill is covered by both classes the character gets to add both class levels. So a Rogue/Fighter would not loose out on climb.
Saves are different too. Instead of having 3 check modifiers, you make an ability/level check against the save target. (using this in 3e, save "DC" levels go through the roof!) If the save is reflex, you use Dex. If the save is Fortitude, you use constitution or Strength, depending on the situation. For example poison would be con, holding open the slowly closing stone door would be Str. Will saves are divided among Cha, Int, and Wis, again depending on the situation. This keeps people from putting their primes in Con, Wis, and Dex and living forever.
Turning in the MOAT engine works like this: The cleric or other class with a turning ability has to beat the base target number (12 or 18) plus the number of hit dice that the undead (or earth creature, or demon, or outsider, allowing for other 3e options) has plus any turn resistance ability. If sucessful, the cleric can turn the monster. The number of monsters that the cleric can turn is based on two factors. If the undead have no int score than the Cleric can turn 1d12 of them (adjusting for cha and greater turning abilities). If the undead are intelligent, but have less hit dice than the cleric, the cleric can turn 1d6 (+ adjustments) of them. If they are intelligent and have more hit dice than the cleric the cleric can only turn one (note no bonus adjustments). If the have 5 hit dice more than the undead they are turning, they can destroy the undead. If they have ten hit dice more they destroy the undead and do the maximum damage.
Thats MOAT!
Aaron.