X-bit Labs learns from this HardSpell.com article (in Chinese) that ATI is planning more value-oriented DirectX 9.0 graphics cards in the form of their new "Radeon 9550" lineup. According to the article, the Radeon 9550 is essentially a slower Radeon 9600, which means that the new GPU may likely be a down-clocked RV350, with 128MB DDR SDRAM on a 128-bit memory bus.
"Graphics cards based on the RADEON 9550 will work at 250MHz/400MHz speeds for chip/memory, 75MHz below core clock-speed provided by the RADEON 9600. Additionally, ATI may roll-out a version of the RADEON 9550 with 64-bit bus. Sources assume that the price of the RADEON 9550 that is expected to be formally announced in early April will be in the range of $70 - $85."
This means that ATI may offer two versions of the Radeon 9550, a vanilla version featuring the 128-bit memory bus, and an "SE" version which will feature the same core/memory clock speeds, but with a slower 64-bit memory bus instead.
For pictures of the GPU and reference card itself, please check HardSpell.com's article.