Is there any way to dual boot on the international GT-n7000 phone ? I have no tried the CWM backup / restore to switchbetween two ROMs but I would guess no issue with that to be encountered. Just that it would be too cumbersome.
The answer to your question is extremely complex and (in my opinion) not material for SE since there are a lot of files that you'd need to download and cannot be hosted here. Fortunately, XDA has a thread for multi-booting on the GT-N7000. I also found this tutorial on YouTube so that you can see how its done.