Howdy Mike,
That is awesome!
To a reasonable extent you are in luck. Our tickets framework, which is built-in to The Events Calendar, is pretty comprehensive and flexible. We currently support 4 WP Shopping carts: EDD, Woo, WPEC, and Shopp. WPEC tickets is our most recent addition, and the main class file which power nearly the entire plugin (by extending the tickets framework) is only 900 lines of code. There are a handful of other files/classes in that plugin, but they mostly relate to activation and licensing.
Would you be interested in sharing or trading your work on this? Also, our next release, 4.0, features many enhancements and more than a few changes to the tickets framework. Would you be interested in beta testing it so you can gets your hands on the latest code?
Does that answer your question?
Cheers!
– Brook