Some of you more ambitious folks might want to check out this;
What is it you ask?
GtkRadiant is a free program built from the open source code of QE4, the program Id Software uses to build maps/levels for Q3A Arena.
Raven most likely uses a highly personalized version of GTK or QE4 to develop levels for JK2.
And someone (cough...cough...maybe you...cough...cough) out there might think that you might want more than 12 multiplayer levels....and sometimes some of the best stuff comes out of the community.
Modification and community expansion of a game is what keeps it alive. Its the reason Quake 1 has STILL got servers on the internet today...not to mention Quake 2 and Half Life and all the mods for Q3A.
While Lucas Arts hasn't officially released a statement pertaining to the legal aspects of JK2 modification and 3rd party mapping. I'd think corporately they'd be blind to the point of stupid if they didn't realize the massive staying power community expansion gives a game.
So just a heads up, if your interested in getting deeper into JK2, maybe developing the next Canyon Oasis, or a The Edge (Quake 2 reference) for JK2 saber enthusiasts, GtkRadiant
is the place to start for the tools, and the knowledge it takes to work and build in this awesome game engine.