Their is already a 3 book trilogy set 5 years after Return of the Jedi, by authro Timothy Zahn.
1. Heir to the Empire, 1992 (ISBN 0-553-40471-7)
2. Dark Force Rising, 1992 (ISBN 0-553-08574-3)
3. The Last Command, 1994 (ISBN 0-553-56492-7)
although according to wikipedia:
http://en.wikipedia.org/wiki/Sequel_trilogy_(Star_Wars)
"Although no longer widely accepted, it was once commonly believed by fans that Timothy Zahn's novels Heir to the Empire, Dark Force Rising and The Last Command formed the sequel trilogy to the original films. Revelations in the plot since the 1999 release of Star Wars Episode I: The Phantom Menace, however, have shown that Zahn's novels are incorrect on numerous details.
having said that, since they obviously can't use the original cast, maybe another trilogy set will be well after this period."
according to wikipedia:
http://en.wikipedia.org/wiki/Sequel_trilogy_(Star_Wars)#Current_possibility
"Currently, there are no firm plans to produce these films. Lucasfilm's stance is that the six Star Wars films comprise the entire story Lucas intended to tell, despite mentions to the contrary in the press and official publications over time.
In a 1997 issue of the Star Wars Insider, Lucas said "[The whole story has] six episodes....If I ever went beyond that, it would be something that was made up. I really don't have any notion other than 'Gee, it would be interesting to do Luke Skywalker later on.' It wouldn't be part of the main story, but a sequel to this thing."
In a 1999 interview with Vanity Fair, Lucas denied ever having any plans to make nine Star Wars movies. "When you see it in six parts, you'll understand," Lucas said at the time. "It really ends at part six." When asked about the possibility of someone else taking over the film franchise, Lucas said "Probably not, it's my thing."
After finishing Revenge of the Sith, Lucas restated on several occasions that he had no plans of making another Star Wars film trilogy. However, Lucas has been known to say one thing and do another in the past, so, many fans still hope that he may pass the project to someone else while controlling it behind the scenes, or that he may reconsider and produce another set of films after more time has passed, probably relying on further leaps of the computer technology. Given the popularity and financial success of the films and the overall franchise, it is possible that Lucas, his heirs, or his businesses may find the possibilities of further movies too lucrative to resist."
