Hi there--
I have done a basic review of this module and have some comments/questions.
1. Why is this not available on Drupal.org? It's the central place for drupal modules and would make this code much easier for more sites to integrate.
2. Why are all of the function names call_function_xx? This makes it extremely hard for other people to use/improve this code. It would be very helpful to use the proper drupal naming conventions for function names. This will also help you recruit more people to support this module.
3. You might consider separating the site map functionality. there are a number of these modules in the Drupal contrib space, so it would be good to give this as an option and not necessarily tie it directly into this module.