DVDWizard looks encouraging - thanks for the link. I will give it a try.

>>>Technically, this is not exactly what you are looking for.
hmm...in a previous mail on this question, the main menu was suggested to be done via vmgm. I guess, this is an example of the following statement from the dvdauthor man pages. :-)
"One of the most frustrating things when deciding how to author a DVD is that there are often many ways to accomplish the same task."

I am working on Ubuntu-13.10, 64-bit; so, no issues with *nix ! ;-)