Getting Aegir to provision a lot of sites
The Aegir feeds module exposes the key details to feeds, so that it can create site nodes. Whip yourself up a feed importer preset with the source of your choice, create site nodes and map your values to the servers and install profile that you want Aegir to use. Simples.
Aegir is designed around custom node types, and it is a total pain to get default values for some things, so this approach may have massive limitations, but I've just created 500 sites on my local testing Aegir, so it does work a little!