I bought mine directly from inforce (
http://www.inforcelive.com/index.php?route=product/product&f...). There are a few similar boards like the odroid-xu, but the IFC6410 is currently the only one with both SATA and real gigabit ethernet, not something attached via USB.
And it uses the GPU with the best open source driver support (
https://github.com/freedreno/freedreno/wiki/Ifc6410), so it runs the full Gnome 3 desktop and even weston/wayland.
There's a small community forming around the board, so there's some degree of support available. But currently it's not comparable to what's available for the Raspberry PI, you still need decent linux skills to set it up. But that's half the fun anyways.