A few things have been said about third trilogy over the last 20 odd years, but SHOULD it ever be made, these ideas may change, just as this current trilogy contradicts earlier information given about it.
George Lucas told Starlog in early 1981 that the ninth film would have 'The End' written at the conclusion, and he would feel very satisfied to see that appear on the screen.
Richard Marquand (director of 'Jedi'

told Prevue magazine in '83 about a being powerful enough to control the fate of Luke Skywalker. 'You'll be amazed,' he said.
At the 1987 Star Wars Tencennial in Los Angeles, George Lucas was asked why Luke never gets a girl, and he said, 'You haven't seen the last trilogy yet.' (Of course, this defies, 'A Jedi shall not love.'
Prior to the release of the Special Editions in late '96 (or there about), Mark Hamill told Starlog that he had already discussed with Lucasfilm the possibility of playing Luke as an elderly Jedi a la Alec Guinness's Obi Wan in future films. (This was before Lucas announced he doubted the third trilogy would be made.)
Some of the Star Wars books, which take place after 'Jedi,' feature three offspring of Leia and Han: Anakin, Jr. and twins Jacen (sp?) and Jaina (sp?), all three training to become Jedis. My understanding is that Lucas had approval over plot developments of this magnitude, so my assumption is that this would happpen in the films (just as events in the book Splinter of the Minds Eye occurred in ensuing Star Wars