Quote
Time May 23, 1983
"The sequels, the three movies that would follow Jedi, are considerably vaguer. Their main theme will be the necessity for moral choices and the wisdom needed to distinguish right from wrong. Luke, who will then be the age Obi-Wan Kenobi is now, some place in his 60's, will reappear, and so will his friends, assuming the creator decides to carry the epic further."
If we look at just this one entry and if Lucas decides to do a 7-9, we should expect them to come out in roughly 10 years.
Why??
Mark Hamill was born in 1951, making him 52-53 right now. In 10 years, he'd be the right age to reprise his role.
(I'd personally prefer to see some visual production of the books.)