Quoting Darren Oh <darrenoh@sidepotsinternational.com>:
So far this whole discussion seems to be a case of ask the wrong question, get the wrong answer. I have seen no evidence to suggest that one cannot write some code that depends on non-free software, release it under the GPL, and have the GPL apply to that code. What would be against the spirit of the GPL would be to write code that depends on GPL software and to release only a compatibility layer under the GPL, keeping the main functionality non-free. Since 1) the third-party apps that are being integrated do not depend on Drupal and 2) the module authors do not own the rights to the code in the third-party apps, this issue is irrelevant to the situation under discussion.
That is how I see the issue. I have two different components one GPL licensed one some other license. I need to write software to communicate between the two. I have the right to license it as I see fit. Since I wish to use the Drupal methods of distribution I need to use GPL. I also have the right as the copyright owner to license this new work under some other license. Earnie -- http://for-my-kids.com/ -- http://give-me-an-offer.com/