[development] Allowing users to create easy pre-fab sites?

[Bob Fishel]

Is anyone aware of anyone using Drupal as a hosting system.

My goal is to allow users (probably through OG + Domain Access +
Domain Access Advanced + ubercart) to purchase a hosting plan and
automatically have a domain set up for them.

My users are all in the same industry so the type of nodes they will
need to create can be boiled down to a simple 3-4 types.

Basically I want them to be able to:

1. Be assigned a template domain/site with some default pages with
some lorem ipsum text (should be easy to accomplish using rules)

2. Be able to switch themes on their domain only (I'm not sure how to do this)

3. It'd be totally awesome if they could modify there themes by
dragging and dropping blocks to change the layout of their particular
site (again no idea how to do this)

4. Grant other users the ability to edit their site (I'm not sure how
to do this without exposing my entire user list to them....)

Thanks

-Bob