PHYTEC just registered their low-cost, open-hardware OpenBoard-AM335x with 512MB DDR3, 512MB NAND and 8MB SPI flash
http://beagleboard.org/project/openboard-am335x/
U-Boot patches welcome.
PHYTEC obviously have very odd definition for OpenHardware there are no CAD files for these boards, so they are CLOSED hardware as everything else produced by this company