Apple did have the datacenter-designed Xserve for quite a while, but when they went into retirement Apple fans were left with no alternative. But there is someone who has thought of a way around this.
Over at Steve's Blog, who is anonymous, he has thought up of a solution to Apple's Xserve who has disappeared from the market. "Steve" has worked with vendors to developed a custom 1U shelving, cooling from car radiators and four-in-one power cables that cram 160 Mac mini's as well as a managing Xserve into a single enclosure.
This is quite the feat considering 160 machines would all obviously run hot, and we all know heat rises. Each machine sports a quad-core Core i7 processor and an SSD and this cluster features double the cores at 640 cores, when compared to the competing Xserve cluster. There's power consumption savings and a 45-second, network-controlled reboot with the cluster.
There's a bunch more reading to be done - but the gist of it is quite the feat!