Am now successfully running multiple sites on a single instance of Orchard (this one). Can’t really divulge what they are, but I will comment on the configuration- when making a new tenant, make sure you have no spaced in the name. It doesn’t fail immediately, but does a few steps later. The solution requires – 1. shut down the orchard website instance 2. open the tenants subfolder in the app_data and find the offending folder with spaces in the name, and delete it. 3. restart the website.
Note that even if you abandon an existing “spaces in name” corrupted attempt, it will still blow up every time you try to create a new one until this is resolved. And, if you don’t shut down the site first, it will keep recreating this messed up folder. fun times.