For actual Epic level, meaning above 20th, Dungeon has published two: In issue #93 they did the first one, called "The STorm Lord's Keep", designed for 21st level and meant to be a first Epic-level adventure for characters who've just hit 21st, and then in issue #123 they have "The Quicksilver Hourglass" which is designed for 30th level.
Storm Lord's Keep is the better of the two IMO, because it's longer; it involves invading a cloud-island populated by powerful Cloud Giants with lots of class levels whose leader guards a secret at least one god would rather not see released. Quicksilver Hourglass features a 4-dimensional dungeon and a fight against a demigod, but is really quite short overall.
Now, if you want just High-Level adventures, for levels 15+, there are a lot more options. Dungeon alone has one in nearly every issue for the last few years; every few months they'll do the "high level" adventure at 13th, but usually it's 15th or above. Several of theirs have been very interesting in breaking the mold of a typical adventure setup. The adventure titled "Diplomacy" in issue #144 (the current issue as I type this) is notably good this way. It involves the PCs being hired to negotiate the rights to a planar treasure trove, and delegates from such places as the Plane of Earth, a Modron from Mechanus, and an Arcanaloth from Gehenna are all involved. I enjoyed/admired the writing and thought put into the modron's arguments particularly.