An epic superadventure in the 13-14th level range?

Black ice well is not an epic campaign. It is a decent sized book, but it is basically a dangerous wilderness area with an extremly dangerous dungeon below.

If you are looking for something to take your players up to level 17+, then pass on this.

I assume you are aware that 3.x D&D tends to break down at the higher levels of play.

City of Skulls.

Temple of Elemental Evil, or Return to the Temple of Elemental Evil, depending.

Return to the Tomb of Horrors is a good one as well, so long as you don't mind losing a few characters even if you survive the adventure.