Looks like it that ASUS is working on the ASUS M4A88TD-EVO / USB3. This is a new AMD 880G chipset based motherboard, it's expected to be available for less than $150 and will be available optionally with or without USB 3.0 support.

TPU reports that this model comes in two variants, with or without USB 3.0 support, designated with the -USB3 suffix in the model name. It is a socket AM3 motherboard, supporting the upcoming line of Phenom II X6 and Phenom II X4 T series processors. The CPU socket is powered by a 10-phase VRM, it is wired to four DDR3 DIMM slots for dual-channel memory. Even as ATI CrossFire is not part of the 880G's feature-set since it won't support an external PCI-Express lane switch like the 890GX, ASUS found a way around and provided a second PCI-Express x16 slot, only that this one is electrical PCI-Express 1.1 x4, wired to the SB800 southbridge chip.