I am unaware of any scenario originally being included and i edited the book (Loz please correct me if I'm wrong here). There is nothing on the radar at the moment as to a follow up book.
I feel that the point was to start you guys off and give examples of how a race may create a starport based on their general attitudes to commerce, comfort, other races and so on. By using the main races we ensured that no one was alienated as they are all races that even a rainy day b5 fan would be familiar with. Now you GMs get to go off and flourish in your own creativity with the more obscure races.
Enjoy