I'm not sure where to ask, but I believe this is the place. Is the theme of WPMU Dev Swagger Demo page (http://wpmudevswag.wp-ecommerce.org/) downloadable?
The innate theme of MarketPress isn't so good, and I have been looking around for theme alternatives. I found Swagger and realized it is by WPMU Dev also. I also found http://www.marketpressthemes.com.