Check out this "over-under" design! The RFT-2L19 is made by Neuro Logic Systems, Inc. This beauty was originally made for the U.S. Navy, but can now spend some peacetime in the comfort of your own home.
The NLS site describes, "NLS has released the world's first dual 19-inch LCD in a vertical format. The RFT-2L19 is the world's first dual 19-inch flat panel that fits into 2U of rackspace in a RETMA rack or transport case. When pulled out for use, the 2 LCDs open in a vertical format reducing the amount of space traditional side-by-side units require. The pitch of the displays take into account the optimum viewing angles for the operator and reduces the amount of "up-time" involved in using two separate monitors."