I'm sorry but this seems like a solution that is looking for a problem. Per best practices (and you can ask Mike Jensen at ESRI), in ANY rdbms, you should be creating and using a headless data owner in your rdbms, then assigning privileges appropriate to that owner. DBO or SDE should never own the data or schema, and unless each of your users is an sde administrator themselves capable of understanding and managing sde geodatabase objects, versioning, states, etc. they should never own data either.
For example, on our production geodatabase, GIS owns all data. Users and AD groups are placed in view-only roles. Our production geodatabase is actually the child gdb of our 11 edit user database instances, to which we replicate data weekly. In each of our edit database instances, each utilizes a headless data owner and users are assigned to editor roles with view, create, update and delete privileges.
Thanks
David