We learned that ATI has indeed shipped many RV670 chipsets, but for some reason these chipsets have had a rather hard time finding their place in graphics cards.
Our sources have confirmed that ATI is shipping many chipsets, but the graphics card manufacturers have had a hard time bringing enough products on the market.
We learned that many 3870 and 3850 with 512MB cards are expected in less than a week, and we guess that the shortage is just the usual way of production cycle in these fabs.
We will keep our eyes open for any updates on this matter.