Good question. I pondered the very same question for a while, then I just replaced the whole loading screen thing (took away the frames and everything) with one full screen image presenting the level name and text: Loading - Please wait.
Yeah, I have a nice (in my own opinion anyway) logo roq in the very beginning, followed by the Star Wars and text scroll. I didn't want anything technical looking stuff to ruin the finely tuned artistical feeling of the level launch.
I guess the key to the whole issue is:
This is a line you can find in saber.menu. I believe it launches the original game without the mission loading screen. However, I don't know what is uiscript startgame. Can you edit uiscripts somehow? Or do they belong to the integral SP code?
Frozen by ICARUS