Right now, there are only limited themes available, one UNH-branded and one not. We are starting with a very small set of choices, but may have more options in the future.
The OpenScholar development team has plans on their roadmap to do a major overhaul of their templating/theming tools. That work is expected during the later part of 2017. Once that work is done, we will look at how these new features could be used to allow more flexibility in site look and feel at UNH.