The answer posted by Brenden Kehren answered on February 18, 2015 20:23 on this same thread works - the Kentico UI Wizard component basically uses various Kentico APIs (Table Manager, Document Class Info, FormInfo, FormFieldInfo, etc) to assemble a page type or a custom table definition correctly.
That Wizard's code can be traced through and copied & pasted to construct your Kentico object definition of choice.
I have been able to create a unit test based on the Wizard's code in which I new up Page Types (formerly Doc Types) on-the-fly by calling a method with a new namespace and codename, for headless testing purposes.