It doesn't really have the feel of a clockwork creature to me, but there is a Magical Construct template. In general, you apply it to any corporeal creature that is not a shapechanger, elemental, or ooze. It increases HD to d10, slows them down, armors them up, gives them one of a small variety of special abilities (similar to the various golems), a postive Str adjustment, negative adjustments to Dex, Wis and Cha.Richards said:If memory serves, there's also a clockwork template in Monte Cook's Book of Eldritch Might.
Looks nice, but it doesn't seem to scale very well. You probably want to scale the natural AC and special attacks with size, HD, and/or CR.Mark Chance said:Here's a clockwork creatures template I wrote up for my campaign [...]

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.