I'll show you some of the difficulties I've encountered with trying to change the crew in regards to ship/crew state. Download this:
http://www.mediafire.com/?wr46kk70psvfbhp It's a small part of something I was working on a long time ago.
Extract to MODS folder and enable via JSGME. Run both single missions and note the watch crew's clothing and hat (or lack of hat) with each single mission. Increase time compression to 64 and wait till the watch crew detects the biplane. Note what happens to watch crew. Do this for both single missions. See any problems with the crew?
You'll notice that it's easy to change crew's clothing and hats via scripting. The problem is there aren't enough hats, clothing, etc. to cover every possible face, torso, etc. This is why the devs never implemented it
