Could be custom plasterwork.

Try modulararts.com Looks like theirs to me.

Coronado Stone offers a Wave wall panel product and it looks very similar to this. It is part of their New Designer Series line and images can be viewed here. https://www.facebook.com/media/set/?set=a.358269364189070.108793.155702927779049&type=3
Coronado Stone has a profile on Houzz also: http://www.houzz.com/pro/coronado-stone/coronado-stone-products

We just used a similar product- try doing an internet search for Interlam. They have tons of textures and finishes. It turned out really cool and it's easy to install.

Hi there, this was a "modular arts" product. It's a great product but really demands a qualified plaster/drywall professional to insure it comes out looking seamless

Hi- Try the Art Diffusion line from Interlam. They can be ordered in 4'x8' sheets, but they do custom sizing as well- and can help you lay out the pattern. There would be breaks- but depending on the color and pattern- they are not obvious. Here's a link to their Art Diffusion line: http://interlam-design.com/products/art-diffusion/ .

This particular product is our InterlockingRock Dune™ Panel, you can find more info at http://modulararts.com/.

The modular arts panels are light, easy to install, and become entirely seamless. The concept is similar to drywall. About $14 sq ft. Ships in boxes.

Do you install these over drywall?

Yes, that is the way they are most often installed. There is a method using drywall inserts and screws.