I thought the main benefit of "elasticity" was remove "peak usage" as a primary buying factor. If you have a routine that can run, well whenever, then is EC2 any cheaper than using whatever is sitting around unused in your shop already?
The cloud may be a useful resource, but the size & speed of the cloudrush has been overestimated by the entire freakin' industry. By the time it gets sorted and a mature market develops, Microsoft, Amazon, and whomever else will be taking write-downs on all the obsolete kit they built-up in 2008-2009.