Floating around the 'nets today is this video from the site Tinhte, who claim that the White iPhone 4 pictured above is a prototype running an early test version of iOS 4, featuring different/rejected/unused systems for multitasking and folders.
Both Engadget and 9to5Mac believe this is a real Apple prototype (it's seen running Radar and Touch Fighter, two unreleased apps developed internally by Apple). But still, don't take this video with a grain of salt...take it with the whole damn salt shaker.
That said, using the universal search page to display running apps it's a pretty decent idea (even it takes just as many steps to close out of an app). I also like the look of the folder UI better in this version (but maybe that's just me?) And it's also interesting to see the ideas rejected by a company as demanding as Apple, just to try and get a feel for their decision-making process. [Tinhte via Engadget and 9to5mac]