A new trend in Web Design is creating one page themes…. the links at the top are just linked to a section below … but all the information is captured as one single page. This theme is available for sale at Theme Forest for $43 USD.
Click here to see this theme in action: http://frost.wpengine.com/
Another example is http://demo.awethemes.com/?theme=Viska
When searching for themes always ensure the developer is reputable, theme is responsive (fits all screen sizes) and theme will be kept up-to-date.