Just to remind you: Galatea is fantasy adventure setting that sets itself out with some realistic elements. I've been using a lot of reference and other companies' books to write the setting. The first version will be for the d20 System (OGL) and it will be published with a Creative Commons (Attribution-Share Alike 3.0 United States) license. I.e. the Game Rules will be under the OGL, and the Fluff will be protected by that particular Creative Commons license. This way, I'll be keeping certain rights to myself. That way, those rights will be up for sale: like the right to for a company to keep its derivative of the original Galatea to itself. This right is called the Exclusive Derivative System Right (or more simply the Right to print in the title page of your Galatea derived book "This Wizards of the Coast game product contains no Game System License content. No portion of this work may be reproduced in any form without written permission.")
The World of Galatea and its fluff and rules will be open for anyone who buys it to publish derivative works in any system they wish. GURPS, Rolemaster, D&D 4e, Swords and Wizardry, Palladium: you will be free to republish the World in any game system or make derivative works for that system. This is simply because Intellectual Property is a total myth. Ideas can only live and thrive if they are enjoyed and propagated by all who read, see, and hear them.
If a company wants an exclusive license to publish the World of Galatea, they have that right to seek it. But isn't it easier just to publish your work without the exclusive license? :)