Possible to create new Application Handler? Blender's application handlers are listed here, but is it possible to create a new one?

For example, I'd like an application handler which is a callback for every time I add a strip to the Video Sequence Editor.
The Blender/Python API can’t (yet)...
  ...
  - Define callbacks or listeners to be notified when data is changed.


Source: API docs

App handlers can't be created with Python, they need to the coded in C. The fact that registering arbitrary event callback isn't supported suggests that such an event driven design is not intended in Blender.