Add other content types to OpenAtrium case tracker

I'm building a site with OpenAtrium Drupal installation profile. I want to have multiple content types of "cases" that can be tracked together (obviously they would all share the basic case fields). I'm wondering what the best way to approach this is. Should I make an override module that overrides atrium_casetracker? Should I make a completely new feature?

I've been in this position before. Here's what I recommend.

1. Create your new feature. Possibly even one new feature per case type if each case has a lot of associated configuration and customization code.
2. Modify the casetracker_case_node_types variable so your content type is recognized by casetracker as being a case type. You need to do this before creating nodes of your new case type, otherwise you will have migration complexity. (See http://drupal.org/node/734542 to make that better.) **For compatibility with OpenAtrium's Atrium Casetracker feature, modify this variable with hook_strongarm_alter() to avoid creating a feature that conflicts with Atrium Casetracker.
3. Be sure when exporting your content type that all variables and node options are properly configured and exported with your content type, such as the atrium updates variable and the og usage variable.
4. If you need to change the default case, you can export CCK fields and other configuration related to that node type in your new feature.

If you have questions on this, please comment and I will update my answer to clarify further.