Starting with virtualfs version 1.11, AclFS is now usable. You will find complete documentation in the document virtualfs.html.
AclFS sports 17 different privileges, and you can grant them separatly to one user, a group, or a list. A list is a collection of users, groups and other list.
For a single file, you can grant many privilege combinations. Each combination is assigned to a separate list (of users, groups and sub-lists).