The limiting factor here is that you need your lens to shift focus. So if you wanted to take a-la five simultaneous shots for focus stacking you would need five

The limiting factor here is that you need your lens to shift focus. So if you wanted to take a-la five simultaneous shots for focus stacking you would need five separate lenses at different focal distances. Since five lenses can't occupy the same physical space you're going to end up with five slightly different perspectives. It might be possible to computationally correct the perspective between them to a certain extent, but I'm not sure how good the end result could theoretically be.