Instead of riding atop a steed of flesh and blood, a Steel Steersman commands an automaton of metal.
Class Skills: A steel steersman loses Handle Animal as a class skill, and gains Knowledge (Engineering) in it's place.
Mount: A steel steersman constructs their mount rather than bonding with one. In addition to the normal traits of being the steel steersmans mount, the animal gains the Half-Construct subtype, counts as two effective druid levels higher for the purpose of determining natural armour, and starts with an intelligence score of -, causing it to possess the mindless quality. This mindless mount cannot learn tricks, possess skill points, or take feats and does not normally take action. While a steel steersman is riding his mindless mount, he may direct the actions of the mount as a free action, causing it to spend it's actions during his turn.
When the mount would gain the opportunity to advance one of it's ability scores, the steel steersman can choose to advance the mounts intelligence score as if the score was 0. This removes the mindless quality, bestows skill points and feats as appropriate for the animal and it's HD (though it does not get the Light Armour Proficiency cavalier mounts automatically gain), the mount is affected by Knowledge (Engineering) checks as if they were Handle Animal checks, and normal Handle Animal checks are not effective on the mount.
Finally, the appearance of a steel steersman's mount is much more mutable. It may appear as a mechanical vehicle, a half-golem version of the animal, or a fully robotic version of the animal, as long as the appearance fits with the mounts statistics. This modifies the mount ability of the cavalier.
Upgrade (Ex): At fifth level, the steel steersman becomes capable of upgrading his mount's body. All of the mount's primary natural attacks can be improved into masterwork quality weapons through Knowledge (Engineering) checks as they were Craft checks, though only the masterwork component is crafted, and the mounts natural armour can be improved to masterwork quality armour in the same manner.
In addition, you gain the benefits of the Craft Magic Arms and Armour feats, but only for enhancing the masterwork natural weapons or masterwork natural armour of your mount, and the skill used for the crafting is always Knowledge (Engineering). This replaces the expert trainer ability of the cavalier.
Why does the mount gain the half-construct subtype? From your description, it sounds like it should be just a construct.
Overall, a cool idea, though.
Why does the mount gain the half-construct subtype? From your description, it sounds like it should be just a construct.
Overall, a cool idea, though.
Because the full construct type would be a giant buff at the start in regards to to all the immunities and the bonus health, while at the same time the lack of health would be a major weakness at high level since it wont be getting much bonus hit points from size.
... and now I've just noticed that I didn't give it "an effective caster level equal to it's class level." and it appears I cannot edit the post.