I'm considering how best to implement this, and I think what I would do is add [Copy] [Paste] buttons to each page, so you could copy an entire page from the current live set, load a new bank and paste it int, then rearrange as you see fit.
That seems a lot less problematic than allowing an arbitrary selection of slots to be copied and pasted, which would involve unexpected reordering results etc.
That's also very similar to how E.S.P. currently allows the system to work.