Ideal worker PC for large cluster

[chort]

Hey,

I'd really like to hear your opinion of running a pretty large (50 to 150 workers) cluster of PhotoScan machines. What hardware would you pick for best cost-effectiveness and performance in this case?

I am collecting from 9 to 25 photos with 12 Mpx every second, depending on the job, with surveys running for several weeks at a time, and want to have at least a chance of processing it.

Thanks
chort