I was thinking of the same thing as Inminente and Blinghound (
his mockup) but didn't want to post anything because i think that it will be a lot of work to implement these features so that they feel like integral part of the ui and not a gimmick. But since Steven expressed some interest in this i thought i'll also post a mockup. It almost exactly like the other ones with few extra bits.
Tabs are in the caption , but only above the main panel.
Menu Button over the navigation panel. When the left panel is hidden the menu button shrinks to just the icon:
The address bar is more like the one in explorer. Most notable feature - breadcrumbs. Mind blown
. Well maybe not but it would be a nice feature to have.