RE: It only makes sense
Bearing in mind that there are quad, quad CPU blades, I would be impressed if you could find me a quad, quad CPU server In anything less than 2U (sun) and moreU (other vendors I think) And so it's really 10U instead of 20U (at least) :P
Also, having used the blade6000 chassis, the IBM blade centers and the Dell offerings, I'm actually quite impressed with Sun's.
(for example, PCI slots built in instead of occupying a blade slot.. what a novel *read, sensible* idea :P)
http://www.sun.com/servers/blades/x8450/ AMD quad, quad core
And likewise the X6450 for Quad, Quad core Xeon blades.
The blade b1600 did rock, the only downside was like of storage attachment options.