Costs look awesome.. On paper.
Give me the real cost and include an example server spec with cost of the commodity hardware, server, drives, NICs etc. Then factor in the cost of the staff for managing it.
Undoubtedly it will still come in cheaper, but I suspect it won't be quite as jaw dropping.
Doing this can deliver amazing result, but just be sure you know what you are doing, its not always as simple as buying a server and installing the software. I did this and severely underestimated the additional managements requirements, then when one of the boxes started crashing and talking business critical systems with it. With no vendor support we were left to diagnose the problem ourselves, after several very painful days we finally found the cause, but by that time all faith in the system had been lost.