Define success?
User adoption?
Whole of life support and redundancy?
Commercial viability?

I would suggest that there's a few *nix variants out there that already meet any/all of the above.

As far as I can see, and this is not in any way trying to diminish the value and effort of the community supporting it,, Meego has started off as a commercial venture and will live or die according to it's ability to sell devices. Like Android, Symbian, and for that matter IOS, it is a consumer driven OS with one purpose. to make money for the people investing in it's development (Intel and Nokia et al)

The fact that it's based on an open source OS, and has a degree of portability across a number of HW platforms doesn't make it special, just an evolution from an OS that only managed to get out onto the market on 1 device......