Just perusing through, and had an idea you might like (someone may have mentioned it already, I only read the first two pages) but you can use interactions and natural weapons to give the automatons built-in weaponry. Say you have a caste of steel automatons that, instead of having two hands, has one hand and a plasma cannon that fires (ie, can do solid splatter breath attack material emissions that require the body part PLASMA_CANNON or something), where the plasma is a modded-in high-temp material, maybe with some kind of syndrome if you'd like. Alternatively, you can have machine guns, muskets (create a cloud of smoke at the firer when shooting?), auto-crossbows, or what have you. The reason I suggest interactions over weapons is that they're more moddable in terms of range and rate of fire, although less so in terms of projectile shape. Natural weapons would make good cylon-esque claws and such.
I don't know much about steampunk, so I don't know what, if anything, that I've suggested would be thematically appropriate, but it would be cool. For the taser suggestion earlier, short-range interactions that cause burn syndromes and temporary paralysis would work perfectly.
EDIT: Also, re: spawning, I think the other way to create new automatons is to transform other creatures into them via interactions, although I doubt you'd want automatons to create others by harvesting corpses and re-animating them as automatons. Also, armok only knows the kinds of bugs that would cause