It's taken me awhile but after numerous searches and experiments galore, I've come up with a solution I can live with. You may not be able to, but I thought I'd share since quite a bit of folks were trying to do this too.
I tried the disguise method and just got a PC that was Bastila's clone, in whatever armor style I tried to edit.
Solution:
edit appearance.2da by placing Bastila's modelb column entry (P_BastilaBB) in appropriate column as decoded below.
1=a underware
2=b base clothes
3=c g_a_class40xx
4=d g_a_class50xx
5=e g_a_class60xx
6=f g_a_class70xx
7=g g_a_class80xx
8=h g_a_class90xx
9=i jedi robes
10=j revens/starforge robes
Sorry no link but I saved the page and can't remember where I got it. I believe the post I got the decoding from is stickied, Major props to T7nowhere for the referenced post.
Example: if you wanted Calo Nord's armor to look like Bastila's clothes you copy/paste P_BastilaBB into modelg column of appearance.2da for your starting char class as below referenced from Redhawk post (again major props)
http://www.lucasforums.com/showthread.php?s=&threadid=132655)
The player models that are the soldiers have LRG in their label fields such as P_MAL_C_LRG_05, the scouts have MED in their label fields such as P_MAL_C_MED_05. Scoundrels have SML in their label fields such as P_MAL_C_SML_05.
LS: your armor looks like Bastila's clothes.
DS: all armor of that class looks like Bastila's clothes. I've only tried on female pc but it will probably work on male if you want to play crossdresser char.
Now all I gotta do is learn to use PS and I can add some color to clothes for my bad girl. ;)
Thx to all the good folks out for all your help with my modding endeavours.
Shangoman