I can't really speak to the technical steps to do it, but i would assume it's possible, since you can use a custom perimeter for Compare & align. To the second part of Stijn's original post, i don't believe a custom perimeter would allow you to determine to which level of decomposition to duplicate.
We have a similar requirement for moving content from one repository to another: we can't rely on the out-of-the-box perimeter, since in some cases our users only want to move for example a process, its diagram with all the sub-processes but not the diagrams of the sub-processes. With a perimeter, if we define the behavior to go deep on the description metaassociationend, i believe it will also take the diagrams of the sub-processes. One alternative that we're considering is to write a custom macro where we can provide queries at run-time to extract the objects at the level we want for that instance.
It might also be interesting to look at the macro for the out-of-the-box impact analysis report template: when you create an instance of the report, you can choose to what "level" of the object's "neighboorhood" you want to report on. There may be some ideas in there for how to let users select the level of decomposition when creating a duplicate.
