Here is a stackable cube PC case that lets you build killer custom computers. The Thermaltake Core X5 Tempered Glass Snow Edition has a dual chamber design optimized for cooling and performance. It comes with dual 4mm tempered glass panels. You also get interchangeable IO panel locations with 2 USB 3.0, 2 x USB 2.0, and other ports.
These cases are ideal for file servers, dual systems, or high-end liquid-cooled gaming computers. Up to E-ATX form factors are supported.