How to create new Meteor (pseudo?)instances in real time?

This may be way over my head, but I would like to implement something similar to (but not quite). A place where people could deploy their Meteor sites in real time, and there will be access control, i.e. users won’t be able to affect each other’s sites.

Short of running an instance of Meteor per user (each user on a different port and/or host), is there a way to do this?

Have you seen