No you wouldn't. Packed full of generic beige boxes so I hear. Thousands of systems cheap and easy to replace quickly, providing huge redundancy capabilities and load sharing. Impressive, but wouldn't look as slick as a rack full of XServes.
IIRC, I did this a few months ago and the biggest part of the cost of the most expensive Mac Pro was the support option and it was enough that you could pay someone's entire year salary for that much and have them fix all the Macs you need fixed.