Well I've done a little detecting and this is what I've found.
This Vogue pattern is this suit from the Roland Mouret Spring Summer 2006 collection.
Here's a closer look at the neckline.
This is also on my list of new Vogue pattern favorites.
And just for fashionistas sake, this is on my list as well. Not Roland Mouret but based on the very famous RM dress of the previous season.
Which was last year's Vogue Options dress:
I guess Vogue likes Roland Mouret as much as the glitterati does. I wonder if he's seen all the cute versions of his dress at Pattern Review, probably not.