Hi, many website template developers use the default Gantry theme and Framework to develop custom websites. Gantry is a free, GPL licensed, product that is available on the gantry-framework.org website. I would have to see the source code to know if they violated any of the license restrictions, but I can see the Rocket Theme logo in the footer of the screen shot, so I would guess they didn't. It's not a very creative use of the Gantry template, all the elements are pretty much the same as they are in the free version you can download. $60 is pretty steep for this design.
The only themes fully developed, sanctioned and supported by Rocket Theme are the ones you will find on this website. What other developers do with our framework is beyond our control, just as long as they do not violate the usage license.
You are free to use the Gantry Framework for your personal and commercial projects. You do not have to keep the Gantry or RocketTheme links and logos in the frontend, however you must ensure that all copyright notices in the code are retained. Also if you intend to use the Gantry Framework in a commercial project, or a theme you intend to redistribute in any form, please retain a "Powered by Gantry" logo and link in the backend administrative interface.