[James]

Here's some interesting information about designs not used in X-2. Some of which may be seen in X-3. From Dark Horizons.

X3: Production Designer Guy Dyas spoke with Countingdown about all sorts of design work required for the over five dozen sets used in "X2", and talk came up of the inevitable sequel which he says he hasn't heard anything official about as of yet. He did confirm some of the designs they did for "X2" but not used in the film will be saved for future films. Amongst those are the following, see if you can guess which ones will eventually see the light of day: "The Danger Room and the Danger Toom control room (where someone can monitor & supervise the training sessions), Beast and Beast's laboratory, Angel and Archangel, The interior of Alkali Lake's abandoned base which included some very intricate prison cells and a giant cylindrical room where a big mid-air fight sequence was going to happen between Toad and Nightcrawler, a land vehicle that was going to come out of the cargo area of the X-Jet, and a secret level in the Pentagon in Washington D.C.".