There's a very good commentary on Sun's Project Blackbox (see I'll take one datacenter, to go) and Sun's approach to virtualization by Stephen Swoyer (Sun’s Virtualization Push). Stephen makes good points, and ones I can only agree with.

Project Blackbox is a datacenter in a ready to run format, and could be a quick and easy way to setup a 'blackbox' (literally) of computing resource. Merge that fundamental idea with the idea of virtualization, where you can create your own discrete machines (either using Solaris Containers or the forthcoming Solaris on Xen technology). Merge the two with some light desktop devices, such as the Sun Ray or other X terminals, and you could have a complete company computing resource in a box.