'907 Parallax' is an incredibly popular one page WordPress theme has made a ton of sales (more than 7k), and for good reason. The design isn't the freshest but this robust Wordpress theme is extremely flexible and fully featured with a huge array of options. Whether you're choosing between different image sliders or perhaps a video background - the admin area is full of customization options. And for good measure, browser support goes back to IE8. Last but not least a star rating of 4.60 out 5 based on 598 ratings means the support is superb too.
Great one page WP theme with tons of options and features. Not only will the parallax feature be on the main one page, but you can also select a default parallax section and even a "page section" to be displayed across all other pages... and You can change parallax/page sections per blog post/pages, choosing a different one or setting to none.