Tesselator put up a link to the image's source. Apparently, it's an Intel Server board, and is a rackmount version.It is not a Dell board. Dell attach the second processor via a daughter board which also has the associated RAM slots (on the T7500 and T5500 at least). They, like Apple, like to have a bit of proprietaryness (if there is such a word).
Unless it is a Dell server - I don't know what they have in them.
Dell's dual processor machines are expensive, cheaper than Apple but still expensive versus building one yourself but they do negotiate on price and when they eventually hit Dell Outlet with 35% discount they will be almost cheap.