In an effort to increase collaboration and to enable experiences owners to rent out space, I propose a first iteration of parceling of "land" within an experience.
The proposal goes like this. The owner of an experience can define a cuboid space (more complex volumes in the future) and assign some other person with build rights in it. Let's call them a "tenant". That tenant can download the scene for viewing as though they owned it, but not see the owner's assets appear in their inventory. They could not move anything belonging to the scene's owner.
The tenant can place and manipulate objects in the scene, but only within that cuboid space and only things they add from their own inventory. The scene owner and other tenants, when they edit the scene, can see but not edit those objects, with the exception that the owner could move or delete them.
Only the scene's owner could rebuild the scene, unless the owner grants tenants the right to rebuild. This feature could be added later, too.
The owner should also be able to adjust the tenant cube's shape. Tenants would be able to delete objects they own from outside the cube but not move them or add new ones outside their cubes.
I'm proposing this as a starting point because it could have a huge impact on adoption of Sansar, not to mention improving collaboration capabilities. I'm hoping that the way I've defined it constrains the technical challenges enough to make this fast to implement.
The biggest challenge probably will be allowing two people to build at the same time. My understanding is that this is already being worked on. But if realtime shared editing is far off in the future, consider a small modification where a save by a tenant causes a server-side merge. That is, all items owned by tenant Y get replaced by the latest when Y saves. If only owner X can rebuild, there's a basis for changes by tenant Y to inform owner X of the need to download those changes and rebuild. Moreover, a scene could be stored as several packages, where each package represents a user (owner or tenant). Then the merge process becomes effectively automatic, with each save-upload by Y triggering an automatic download to X's client, even while X is editing.
As a side note, the cuboid space is optional. If you take it away, everything described above still works. Then the tenant would have to abide more by an honor system in placing inventory. This is very similar to how many malls in SL work: shop owners get build rights on the entire parcel but must honor the requirement to stay within their stalls.