According to X-bit Labs the upcoming dual-GPU GeForce 7950 GX graphics cards from MSI will retail for about 649EUR (incl. taxes) in Europe. The U.S. price isn't known, but $649 could be a good guess.
Microstar International (MSI), a large manufacturer of graphics cards and other computer components, is reportedly preparing its MSI NX7950 GX2 graphics card, which will carry two GeForce 7900 graphics processors, which, theoretically, allows end-users to install two of such boards into one PC and get a system featuring quad SLI. General specifications of MSI’s NX7950 GX2 graphics cards are very likely to be similar with the GeForce 7900 GX2/7950 GX2 boards: has two GeForce 7900-series graphics processors clocked at 500MHz along with 1GB of 1200MHz 256-bit GDDR3 memory (512MB per chip).