Are you refering to the following technique, or something significantly differnt?:
Notes: This is multi-user that can actually work for some limited use cases (see “use case” below). It is not secure multi-user yet. While it’s useful for running tests and developing multi-user functionality, and it might be useful for the cooperative use cases I mention below, do not assume that it is currently appropriate for giving accounts on your qubes system to your enemies. Some specific security issues (that give good reasons not to use it at this time beyond cooperative use cases…