Have Anakin as shown in the pic that oh_riginal posted and have Ewan McGregor as Obi-Wan with the Episode I or the CG Yoda. Then have Qui-Gon, Padme, a bunch of younglings and various assorted background Jedi show up. Oh, and Jar Jar of course. Then have Anakin ask, "Are you an angel" to the other force ghosts. Luke could also show up, causing the smile on the real Luke's face to disappear, and then the force ghost Luke could vanish again.

Then after Luke leaves with Leia, have a bunch of force ghost stormtroopers come shooting at everybody and the emperor zapping everyone with force lightning (you don't have to show everyone's reaction to this, it would work without it, but maybe have the force ghosts blink out as they're shot.

I don't know how much of this is doable, but do what you can I guess.