open source licence question

[bob 295]

Does anyone know of what I would term an open source licence with a specific 
period of exclusive use?     In otherwords changes can be used in a 
proprietary fashion of a predetermined period (eg. 1 year) and then those 
changes revert to a standard GPL type licence.

Thanks in advance.

bob

--
The Toronto Linux Users Group.      Meetings: http://gtalug.org/
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://gtalug.org/wiki/Mailing_lists