licensing

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