The Inq today confirms the R580 will feature a PCB design almost identically to the R520 boards, with a similar cooling solution and so on.
This card is expected by early 2006 and you'll see some different flavors as the Radeon X1900XL, X1900XT and All-in-Wonder X1900XL graphics cards.
While the first two can get their counterparts from Nvidia, the All-in-Wonder X1900 is going to be "zero competition board"; since nV still has no high-end products featuring TV tuners... and digital DVB-T with GeForce sounds like a pipe-dream.
ATI is also planning a RV560, which will be launched close to NVIDIA's launch of the GeForce 7200, 7300 and 7600. And there's also a new RV530 coming up that will be branded as the Radeon X1700.