As discovered by The Vault user Xporc, the Dead Money BSA file contains the NVDLC02 snowglobe - Zion National Park. This national park is located in southwestern Utah, near the town of Springdale. This indicates that the next add-on will most likely be Honest Hearts, which has been hinted at with graffiti that includes mentions of the Mormon town of New Canaan and Joshua Graham, also known as the Burned Man and formerly as the fearsome Malpais Legate.
New Caanan was originally planned to appear in Van Buren, the canceled Fallout 3 by Black Isle Studios, developed by some of the people who later worked on Fallout: New Vegas, including J.E. Sawyer and Chris Avellone. In Van Buren, it was located in the ruins of Ogden, which is located in northern Utah, but it is possible that it has been moved to Springdale due to the reduced scope of the Fallout: New Vegas map compared to Van Buren, which was to span four states.
Additionally, IMDb is now listing actor Rick Pasqualone credited for Fallout: New Vegas as "Daniel". Daniel was the name of one of the inhabitants of New Canaan in Van Buren. Another new actor listed there is Toby Turner, credited as "Second Narrator".
If you find any other interesting hints at future content in the Dead Money files, please let us know! For speculation on the contents of the other two upcoming add ons, Old World Blues and Lonesome Road, see this post.