There are plenty of examples for using the image-classifier builder, but I have not found any examples on using the generic model builder. In particular:

What would be the input format to the generic builder?
I would guess that I would have to write my own input handler. Where would I do that?
Relating to 2, is there a high level class that I can subclass from to create my own builder?

Ultimately, is there a barebones example somewhere?
Thanks!