Sony unveiling UMD-less PSP with slide-out buttons at E3?

Whispers of a new or revised PSP have been growing decidedly louder as of late, and now 1UP's gotten a ton of new details from what it claims are "sources directly involved with the new system" -- our favorite kind of people, actually. Here's what they were told: UMD is out, replaced instead with options for either 8GB or 16GB of built-in flash memory. Also nixed is any hope of a "PSP-4000," with Sony opting instead to use a subtitle. Three rumored names include PSP Slide, PSP Flip, and PSP Go!, the latter of which borrows from Sony's pre-existing Go! brand and suggests there might be a built-in camera à la PSP-3000's Go!Cam peripheral. The same D-pad, analog nub, and face button configuration remains, but they now slide out from the bottom of the unit (see mockup, pictured). Expected launch is September for Japan and late October / early November for US, and coming with 'em are over 100 classic and new downloadable titles including Gran Turismo Mobile as a headliner. Sony's supposedly going official with all this during its E3 press conference in early June, and for now they're opting to give the staple "does not comment on rumors or speculation" response. That's one mighty intriguing rumor -- we can only hope it pans out.