Take this rumor with a grain of salt for now, but the reader
ChicagoBat, from the site
Batman-News.com had the pleasure to get a tour on the new Batcave that will be used on
The Dark Knight Rises, which is currently housed at Sony Studios. It looks like it will be a little bit similar to the one from
Batman Begins, but with some changes. Here's what he says about the visiting:

Visiting L.A. and had a friend working at Sony Studios show me the Batcave set. It’s half finished, and pretty much looks like the same set we saw in “Batman Begins”. They’re still completing the quarry walls but the wooden manor foundations were all there in the corner. They may add more set dressing with equipment and such but don’t expect a radical redesign as most fanboys are expecting.
Funny thing was I asked the construction guys if they were using the same blueprints/plans from “Batman Begins” to match continuity, they said no, but as the set resembled the cave from “Begins” and I’m a detail freak who knows the movies, (right down to the waterfall entrance where the tumbler flies through) while they may have had new blueprints I could see it was the same cave from seeing the foundation beams that were iconic from the first movie. Also the stage can hold water, they’ll fill it when the quarry wall work is finished and they pull all the rigging lights up to illuminate the set.
With a cast that includes Christian Bale, Michael Caine, Anne Hathaway, Gary Oldman, Tom Hardy, Marion Cotillard and Joseph Gordon-Levitt,
The Dark Knight Rises is set to come in July 20th 2012!