Very nice. I've been using @mmccoo's script manually for a while, so I'm looking forward to trying yours. From basic testing, there are two things that I'd love to see you implement:
x-offset and y-offset would be nice to have in the same form
Updating cloned layouts.
The second is the big one, I know. But frequently, one needs to tweak the layout of your master and propagate to the rest of the board. While you can always select/delete/reclone, this is tedious and you often need to work around non-cloned components. I'd suggest that you can use the timestamp to determine which components are cloned. Maybe pick a "magic date" number that the clones can use? Or, set clones to the tstamp of the master?
That said, thanks for sharing a really useful tool!