Well as you all probably know or read by now that they are coming out with even more re-releases of star wars, They are coming out with a fully 3D Clone Wars series, AND The live action TV Show is coming in about 2 years.
I wouldnt be suprised if they did make another Star Wars game though im not sure if they would do an acutual JK4. Most likely like most companies they would try a new approach and switch development companies(or at least development teams) for the game so it would make the game fresh and new. The game itself would be pretty different from the other game (especially since most likely they will be changing games engine as well)
Now I have heard from IGN themselves that they may be a chance of a Star Wars game heading for the Nintendo Wii in the distant future which would take advantage of the Wii-mode and most likely its online capabilities. If you wish to see that for yourself you can head to IGN.com and search for it yourself.
I would be looking foward for the Wii Star Wars game the most if there is going to be one just because I would love the interactive feel of the game.(the only reason I even started playing jka on the pc is cause I felt it was alot more interactive with a keyboard and mouse.)
*Update* IGN has also CONFIRMED that there is most likely going to be on the PS3 as well. There was reportedly a small video released at E3 about this hush hush project. go check it for yourself. Heres a link.
http://ps3.ign.com/articles/705/705550p1.html