ice wind dale and amn come to mind
Amn would qualify, but Icewind Dale, even by its own description, is podunk nowhere.
How many *major* areas of Faerun are there anyway?
Well, we've already seen the Silver Marches and Unapproachable East. I could easily see a Lands of Intrigue book (Calimshan, Chult, Lake of Steam, Shining Sea area), a Sword Coast book (Western Heartlands, Waterdeep, Tethyr, Amn, Moonshaes, etc), and a Dalelands/Sea of Fallen Stars book (the Dales, Cormyr, Sembia, SoFS, Vilhon Reach, etc).
That would cover most of the major bases. You've still got the Shaar/Lurien/Halruaa, the far north, and the N/NE of the SoFS regions, but there's not alot going on there that springs to mind as book-worthy at the moment.