Gainward has an interesting card in its ATI line, with a prety suggestive name: Gainward HD4850 512MB DisplayPort Golden Sample Goes Like Hell edition.This may be the first HD 4850 graphics card equipped with GDDR5 memory (4850 is normally equipped with GDDR3 memory).This card has a 700 MHz GPU and memory at 3600 MHz (256 bit) is equipped with DisplayPort, DVI, HDMI and VGA.

I don't know the price at this time but this card, if overclocked to close to 750MHz core, should be able to match the performance of HD4870, likely at a lower price.