I'm pretty confident when I say this is the very first transparent theme for Joomla and there is no surprises it's come from RocketTheme.
Basically, the whole theme is developed so the background image is the focus and because of this there are a limitless amount of theme variations.
This is a frustrating time for any member of RocketTheme because the themes just get better and better each month. If you're a member you've probably downloaded it already, if you haven't you will and if you're not a member, but you're serious about themes, then you really should sign up.
Alternatively, just click here for more information or a demo.