licensing

I want to use Drupal as a paid service for building Web sites and communities. The Drupal instances and modules would reside on my server. So basically I would be acting as an Application Service Provider. If I pursue this endeavor I will likely end up using the Drupal core, some contributed modules, and several custom modules.

Does the GLP License require me to make available any of my custom modules, configurations or patches made to Drupal?

I am not a lawyer. Item #10 of the licensing FAQ asks a particular question (my emphasis throughout):

10: Can I write a "bridge module" to interface between Drupal and another system or library?

but then goes on to answer a slightly different one (with specific regard to incompatible licences):

http://drupal.org/project/wysiwygpro

Is something like that allowed:
A) on drupal's CVS
B) at all?

I recently posted a long article on music publishing that was inspired by the various discussions we've been having in this group (from Dubs comments especially). The basic points made in case you don't want to read the whole thing:

1) Do-it-yourself Publishing