Thinking out loud, haven't tested or tried. The model classes are part of the app so you cannot exclude them directly.

I think there is a sneak around it. You probably set-up your model to load a schema, right? The schema class can be part of the config for a model. So I would just neuter the model by changing the schema to something harmless or empty.

The underlying lesson/point being that anything you want different between installations of a Cat app needs to be config based and not in the M/V/C spaces. Though there may be some startup/loading magick that could be applied here.

Or your installation script (Makefile.PL maybe) could strip/add the model as appropriate. I'm trying to sort out a similar issue with a project where there will be a lot of per installation customization, so if you come up with anything nice, please share!