Here's the problem as I see it. You will have to extend the existing circuits to reach the new location.
You can't pull all new circuits through the house so you will have to splice on some extensions to reach the new location. All splices have to be accessible and enclosed in a metal box.
In summary, your splice box will be in your new bathroom and still in the way of the remodel job.
I would have to say that this being the case, the effort and cost is not worth the end results.