This news is slightly old but still interesting, it looks like the Jim Henson Company is planning a sequal to the Dark Crystal:
Genndy Tartakovsky to Direct
Power of the Dark Crystal
http://www.henson.com/company/20060201.html
Award-winning animation director Genndy Tartakovsky, who created the hit series Star Wars: The Clone Wars, Samurai Jack and Dexter’s Laboratory, will direct Power of the Dark Crystal, the much anticipated sequel to The Jim Henson Company’s 1982 classic fantasy film. The announcement was made today by Lisa Henson, co-CEO of The Jim Henson Company and a producer on the film.
Additionally, Tartakovsky’s newest venture, Orphanage Animation Studios, has been brought on board as a producing partner to head up the CG animation elements that will be incorporated with the film’s live-action animatronic characters. Legendary fantasy artist Brian Froud, designer of the original film, will return to design the new characters. Odyssey Entertainment is representing worldwide sales and distribution on the film.
Set hundreds of years after the events of the first movie when the world has once again fallen into darkness, Power of the Dark Crystal follows the adventures of a mysterious girl made of fire who, together with a Gelfling outcast, steals a shard of the legendary Crystal in an attempt to reignite the dying sun that exists at the center of the planet.