You could give "K9Copy - KDE tool to backup DVDs" a try.

It's very much capable of disassembling the individual streams, putting them back together (even customising the selection of audio/video tracks) and then burning it to a new disc.

It seems it's not even capable of putting a region code onto a blank DVD, so (ab)use that as a feature!

A sort of dedicated tutorial on how to do this is on this random blog. Comes down to:

1. Select DVD source.


2. Select "Rip and encode" as destination.


3. Select the elements you want to "rip". It's useful to leave out some unwanted streams/titles/chapters.


4. Select some encoding options, but just use "copy" to leave the contents of the streams untouched.


5. Once finished it will ask you to load a blank DVD to burn.