AMD will be back on the GPU offensive this fall with new offerings. According to DigiTimes, Radeon HD 6000-series will launch first with the HD 6700, which will replace the market currently occupied by the Radeon HD 5770 and 5750.
While AMD's exact launch plans are still unknown, today we get to see some supposed leaks thanks to Chinese source Chiphell. Posted on the forums are pictures of Cayman and Caicos engineering samples, which are believed to be the "Cayman XT" Radeon HD 6870.
The other card is presumably Caicos, which could be part of the Radeon HD 6300 series for entry-level or HTPC. This example has 1GB DDR3 64-bit memory, with a core clocked at 650 MHz and memory at 800 MHz.
This is what the chip looks like, and it supposedly scores P17xx in 3D Mark Vantage, which compares to the P12xx to P13xx range on the HD 5450.
(Images from ChipHell via VR-Zone.)