There is no work that would change the position of Ubuntu with regard to
derivation. Our rules boil down to:

 * join the Ubuntu community and work together with us in the archive
(as most long-term projects do), or

 * ask Canonical for permission, which has been granted to hundreds of
projects over the years

You need to ask Canonical's permission to make a derivative of Ubuntu. This is a very clear statement from Mark Shuttleworth that Ubuntu is not Free software.