I saw this in the news and thought it could make for an interesting render farm. It would be nice if they had access to more memory though (8GB max), hopefully future iterations will allow for more memory. Each 4U unit hosts 45 tiny machines with dual core Atom processors at 1.6 GHz or 2.0GHz with some other basic components like a NIC and SSD.
http://h17007.www1.hp.com/us/en/enterprise/servers/products/moonshot/index.aspx#tab=TAB1
Supposedly the second or third generation of the product (they call it Moonshot) will use ARM processors instead of the x86-64 based Atom processors. Houdini is in a unique position to take advantage of hardware like this because the Mantra licenses for each render node are included with the Houdini licenses, for example with Renderman it would take $90,000 of licenses to run a single 4U unit of these machines. I wonder if SESI has experimented with ARM builds of Houdini or Mantra.