What steps does it take to get there? I would like to see if there is a point for effective application of my humble efforts to make it happen.
For starters there are a few things.
And now for the kicker: there is absolutely no information on the Ubuntu sites on how to get an official status. So to get official status Canonical probably needs to ask you and not the other way around and they will only ask you if it is something special.
Look at the biggest not supported spin-off of Ubuntu: Mint.
It got a lot of traction. On distrowatch it is even above Ubuntu but it seems it is not unique enough to get official support. Ubuntu + MATE desktop is not already an official version, they have a lot of users apparently (or a lot that visit distrowatch ;) ). I do not know how many people are working on Mint but if they have an amount roughly equal to kUbuntu I myself would not mind an official "mUbuntu" version.