Newegg is getting really annoying, stocking, then selling out, then stocking, then selling out. They are a retailer, they should keep stock for what ever they advertise, even though these 6990's are in stock, many other cards keep popping up and they cannot keep them on stock.
They have real time inventory that gets updated based on what gets delivered and scanned in at their warehouse from the suppliers and when buyers purchase all that they received then the item goes OOS until the next shipment comes. Nothing Newegg can change about that other than do like what TigerDirect does where they take a bunch of orders for an item they have not yet received delivery for and then when the shipment gets delayed or never arrives your just out of luck.