In the mini-itx space, there's also http://asrock.com/mb/Intel/X99E-ITXac/index.us.asp which is DDR4, not SODIMMS, and your choice of processor, including V4 Xeons. I have one with a E5-2680V4 + 64GB of ram in it. (128 should be feasible with 64GB sticks as far as I know, but as they're about $700 each last I checked I haven't tried it.)
