The problem for most enterprises is that this is more compute power than they will ever need! If you are a Google/Ebay/Yahoo/Amazon/Facebook kind of company, of course that is not true. But these kinds of companies often use alternative products for density, such as multi-server chassis that strip out the management bits of blade computing for a cheaper solution.
I am running Data Center operations with about 200 virtual servers on about 15 vmware ESX servers. But when I look at the details, and the future, I could imagine running them all on one box within a year or two. Most of these ESX boxes run pre-nahalem intel CPUs, where 4 physical CPUs are easily outclassed by 2 nahalem-based CPUs. With an 8-core CPU (or a 12-core AMD cpu) perhaps we could go 4-1, roughly 2 years later. My old 4U servers with 128GB RAM are being replaced by 1U servers with 192GB RAM. If this trend continues, I'll have 1U servers with something like 512GB within a couple years, maybe even 1TB of RAM. Large enterprises need this kind of power for very few needs other than a virtual server infrastructure.
New single high-power systems are replacing use cases for the blade chassis of yesterday.