Good luck finding one. There is only one set of chipsets available for 771 boards and intel holds the monopoly there - and it shows!. If you are looking for one with a good selection of PCIe slots, well, good luck. :twisted:
To my knowledge there are no boards with real PCIe 16. Some have a 16x slot but are only connected 8x. That´s not that bad since most have only 8x slots and onboard graphics.