How can I calculate costs of deploying 1000 instances of Drupal?
In reply to 'Would Amazon EC2 / Google / Azure be cheaper than having dedicated servers?'

I've done a lot of investigating into this and in every case they are NOT. 

80 Linux servers running 24h/365 - annual cost:
        Total cost per year
Google  £37,515.46
AWS     £29,196.53

These costs do NOT include data transfer.

You can buy a dedicated cloud appliance for less than £50k, fully supported, that will run more servers and last you 3 years (min).