I'm hoping to use Amazon Elastic Compute Cloud (EC2) for an upcoming project that involves multi-hosting a bunch of Drupal websites. I like the "pay for what you use" model, and the ability to ramp up capacity within minutes instead of weeks. Integrating one of Drupal's provisioning solutions with Amazon's "Datacentre On-Demand" is my ultimate goal.

But first, EC2 has a few limitations which makes multi-site hosting a little more challenging: