Crafting a Carriage (or a car, or keelboat, etc.)

[DetectiveKatana]

So UC has some good vehicle examples, which are fine. But are there any guidelines for statistically building a vehicle. For example, if my character wants to build his own custom, alchemy powered walking fortress, how would I go about making this a reality?

If there are no existing rules I can work them up, but I figured I'd see if they existed.

[Eridan]

Not easy to answer and definitely house rule territory.

Some suggestions from my side:
Without magic you cannot do this.
Without heavy GM assistence you cannot do this.
Without a lot of money you cannot to this.
Without a lot of power (high caster level) you cannot do this.
Take a look at items like Instant Fortress, Cloud Castle Of The Storm King. They need an CL of 13 or 20. The witch has a grand hex 'Witch's Hut' that needs CL 18.

To let a vehicle or structure move you can use 'Animate Object' with 'Permanency' or similar powerful ability on its legs. The base price is that of a normal vehicle/structure with an additional 50% for a harder structure (a normal house is not build for moving around). At last magic is needed to gain controll over the animated objects.

Maybe the construct construction rules from UM are another possible solution.

The easiest way should be a 'Wish' or the creation of a new spell (some kind of 'Animate Fortess') with a similar CL.