Packaging cross cutting Catalyst features

A recurring subject on the Catalyst mailing list is about packaging functionality that is not entirely comprised in one of the Model View or Controller parts of the framework (and is not a full application on itself). This is hard and still there aren't many CPAN libraries that do that. One solution to that is writing "helpers" that generate the integration code into your application files. As with all code generation this solution creates many new problems - and ideally we would like to avoid it.

To try out what can be done about that I decided to write a generic comment system for Catalyst (+DBIC, TT and FormHandler). I've already posted the the first code samples to the Catalyzed wiki. The form code and the controller stuff seems closed - it does not need to refer to things from outside but in the DBIC declarations the belongs_to relation of the comments needs to relate to an external table and it's primary key (I assume that comments belong to an article/post/something). How that can be made configurable?