The main issue I would see impeding this is power draw and heat. Unless you are rigged up to run this many machines (including appropriate UPSes) you may run into blowing fuses and needing almost as much power for air conditioning as you need to run the cluster.
If you had like 50 SoCs maybe, because the power draw and heat might be manageable. Something like a RaspberryPi or OrangePi.