"it would be interesting to see if there's any way to construct a license such that that's not an option"
A license I've been working on drafting, copyleft-next (http://gitorious.org/copyleft-next/copyleft-next/blobs/raw/master/Releases/copyleft-next-0.3.0), has a clause designed to make the license non-copyleft if the copyright holder attempts to use its copyright power to offer proprietary licenses. See section 7. - Richard Fontana
Re: I think it is a better model than Android
A license I've been working on drafting, copyleft-next (http://gitorious.org/copyleft-next/copyleft-next/blobs/raw/master/Releases/copyleft-next-0.3.0), has a clause designed to make the license non-copyleft if the copyright holder attempts to use its copyright power to offer proprietary licenses. See section 7.
- Richard Fontana