Radeon HD 4850 and 4870 for Mac Pro?

According to several sources (among them Mac4ever), if AMD/ATI does not currently plan to release a Mac Edition of its new flagships Radeon 4xxx X2, it should nevertheless offer in a near future the Radeon 4850 HD and 4870 HD for the Mac Pro.
As usual, one does not know how far is “near future”. Indeed, so far Mac users have always been at least one generation behind concerning graphic cards offer; without mentioning that we have to pay a premium price for a product which is not anymore available for PC… in addition, some cards are only available for the US market…