The past 2 years or so, has seen many rumors about expansion to the Magic Kingdom, and in particular the addition of a major Eride - Fire Mountain, Bald Mountain etc...
While we still have no official comment on the existence of these projects, I do have some further clarification on the current state of play.
REMEMBER - this is not official, and may or may not happen. However, the information comes from a highly reliable source within WDI.
The following describes a long term plan for the purposes of dedicating land. It fits with the original property plan, and the 25 year plan (completion would also mean finalisation of the 25 year plan)
MK is to be expanded 85 acres west, 44 acres north and 18 acres east
Addition of Bald Mountain (in whatever form it may take)
Addition of Mysterious Island (Journey to the Centre of the Earth)
A new transportation hub
Access to the WDW Airport
A new small Village area
3 new resorts
Additional backstage shops - including a pyro area
Additional cast housing
Although these items above are in the plan, and land has been designated, the order, and timing of construction are yet to be decided.
REMEMBER, the following descriptions are rumors, not fact.
Bald Mountain is the project based around the Disney villains concept. The new expansion of land across 20k and into Fantasy Land will house this new attraction, and the brand new land to which it belongs. The new MK land, based around the villains is most likely where the whole Shadowlands rumors stem from. The Bald Mountain project is another water based/hybrid coaster attraction, making some use of the existing 20k lagoon and the new area built behind Fantasy Land.
Mysterious Island would make use of a huge area of expansion, behind Big Thunder Mountain. Based on the attraction currently under construction in Japan.
The following description of the Tokyo attraction from http://www.tokyodisneysea.co.jp/english/index.html
"Mysterious Island brings to life the writings of Jules Verne, the father of modern science fiction. Guests can visit Captain Nemo's secret base where he will invite them to become members of his crew for two thrilling adventures. On one, they will plunge to the bottom of the sea and encounter shipwrecks and mysterious creatures. On the other, they will journey to the depths the earth where the only escape route lies through an active volcano."
"Journey to the Center of the Earth" is located within the volcano itself. Riders will travel downward through the volcano in "Enhanced Motion Vehicles" and encounter a large Animatronic creature.