Just a thought

Take an old Sun X4500 chassis. Rip out all the 48 disks. Keep the trays. Rip out the SATA controllers, put in multiport NIC chips. Use otherwise the same backplane. Take the disk trays. Shoehorn PICO-ITX boards into them. Reuse the power and SATA sockets. Boot the boards via iSCSI or onboard flash. Use the Controller Board (the board with the Opterons) as a software loadbalancer, switch, router, whatever… call it moonshining ;)