I love the formation too, I just can't see it working for us for the simple fact that the make up of our squad isn't set for it.
Firstly, I think Carrick is better in a two with more responsibility. He's flourished since he hasn't had to clean up behind Scholes.
Secondly, the two DM spots, say Carrick does take one, we still need another. Say one gets injured? It'd throw the whole system out as two DM's are essential which means we'd have to look for two DM's this transfer window.
Thirdly Rooney, Kagawa and Nani aside, who else could play across that line? Young? He's quite natural at it but hardly inspiring. Valencia would relish the space being so far inside, it would give him acres of room to turn away from his team mates and the goal.
Where would Welbeck and Hernandez get minutes? I'd guess Welbeck in the 3 behind the striker and Hernandez as a back up to RVP.
We could play it and it could work but there does seem to be a lot of potential problems to it. Like you though, I'd love to see it happen.