IMO it's not just pushing the menu on top as a nav-bar and the login above all. There are other questions to be answered before starting, so a few I thought about are:
Do we want to have also a max and min width (as for nuancier) or a fluid layout?
Where do we want to place the "user menu" if the login and the user info are on top? A separate menu item which says "User"?
If we want to make the site close to nuancier we also need a new resized logo, same style and height as 'supplemental wallpapers'.
Do we want a footer on the apps sites to collect them all?

In the meanwhile I can start looking into this.

I'm pushing this back for the moment. I think it will make more sense to change the UI when we change the logic and implement the locations.

I seem to remember you have started working on this. Is your work available somewhere already? Are you willing to continue?

This is now planned for the next release so it's on my radar again :)

Started in the dev040 branch

Ok closing this one