Let modules add library paths

It would be great if either modules could add library paths, or modify existing ones, or if libraries could exist within subdirectories of existing library paths (for organization and deployment purposes).

an example situation:
a project has libraries externally created and internally created and needs them organized w/in the sites/all/libraries construct similar to how modules and themes can be organized w/in their respective directory structures. presently, putting a library into sites/all/libraries/contrib would cause the library to be ignored when searched for.

for now, my proposed solution addresses "adding library paths" which indirectly solves the other two items to some degree. In libraries_get_libraries, there should at a minimum be a drupal_alter("libraries_directories", $searchdir); that allows the paths to be appended to, or modified.

by providing an alter() hook, projects can at least put in a custom specific path that will allow libraries to reach their specific paths. example:

function my_project_libraries_directories_alter(&$paths){
  $paths[]="sites/all/libraries/contrib";
  $paths[]="sites/all/libraries/custom";
}