Yes, Eurogamer’s unnamed source has spoken out again to confirm David Perry’s assertion that the PSP-4000 is real, UMD-free, and due to arrive before the end of the year. The PSP2 may be coming in 2010.
The source also spoke up on the rumoured sliding screen. "The screen is basically the same as the one in the 3000 - except it slides." In the closed position, it’ll be possible to play games that only use the shoulder buttons, such as LocoRoco.
Perry himself has spoken out again, meanwhile, challenging Sony to deny the rumours. “I confirmed with top PSP 2 developers,” he wrote. “John [Koller], state that PSP 2 will have UMD."
Sony is of course refusing to speak out on these rumours, but we wouldn’t be surprised to see an announcement fairly soon.