Anyone interested,
I have released an API for VocalDispatch, as well as added the ability to add custom events/phrases, for use with both default and third party functions. Some ideas of what the API can be used for are:
Providing custom backup behavior during a callout.
Adding new functions entirely (coroner request, etc.).
Adding status phrases that can be used in place of menus.
There is an example project, as well as a step-by-step API usage guide available on GitHub here. Support requests, questions, and comments for the API can be posted either here or on GitHub, I will monitor both.