This is unconfirmed, but according to a poster at Gallifrey Base claims to have details of the new Tardis set for Doctor Who that we’ll see in 2010 with Matt Smith’s Doctor. The interior of the Tardis will have “two different levels, joined by a spiral staircase” with a console room, a lab area, a sitting room, a long corridor, and “numerous other little nooks and crannies.”
“The console room itself is a shaped like a hexagon attached to a square rather than being circular, the color theme is mostly silver and gold, and the coral finish has been replaced with marble. The roundels decorating the walls are now inverted hemispheres, and while they appear throughout the set, they do not appear on every wall. The roundels have different color schemes for each room: gold in the console room, silver, gray, and blue in the lab, and brown in the sitting room.”
The last time the Tardis interior changed was with the 9th Doctor (Christopher Eccleston) to the “Coral” theme for a more organic design. “It is believed to be regrowing itself after the massive damage it may have sutstained during the Time War with the Doctor making do with anything for its controls and the TARDIS subsequiently intergrating them…”
Below are pics for your reference. Let’s see how the Tardis changes!
[Source] io9, GallifreyBase, Tardis Wiki