Tyan Transport GS12 and GX21 1U rackmount servers
 

If you want to pack a bunch of full-featured basic x86 servers - with at least one big hard drive each, nothing much shared, and at least a current-issue desktop processor, not some low-power basic chip - into a small space, your only option is rack mounting.

People who only need a few servers can make do with standard tower or desktop enclosures. But you can fit a proper server-class PC into a "one unit" (1U) rack enclosure, and by definition that means you can have a whole server that takes up only 1.75 inches of vertical space. Forty machines will fit in a rack that's shorter (though not necessarily lighter...) than the average human male, and it's no big thing for them each to have two hard drives and two CPUs, if that's what you need.



http://dansdata.com/ttransport.htm