Kevin Rose rumored a newer, trip'ier, more galactic iTunes visualizer, and now according to MacRumors, he's confirmed where it comes from:

Magnetosphere had been available as a free download from the developer's site until a few months ago. The author has since responded to an inquiry by Allan White that the plug-in had been "sold to a third party".

Since CoverFlow was acquired by Apple and integrated into iTunes (before progressing into Mac OS X 10.5 Leopard's Finder file browser -- and the iPhone!), this certainly has precedence.

We'll find out for sure on Tuesday!