You can, now that /loadui is fixed. Or enough to give characters seperate UIs, at least.
Step 1: Delete the eq2.ini file.
Step 2: Log in with one of your characters.
Step 3: Use /loadui. (Not sure whether you have to use the menu or type out a folder name. May be that either works.)
Step 4: Log out before doing anything that may cause a crash or update your character's settings file (opening options window, etc.).
That character should now be using a custom UI, without the ini file. Characters that don't use /loadui should still use the default.
That's what I understand from reports, at any rate. My account was already cancelled by that point, so if that works you'll have to talk to someone that still plays.
Edit: Here's the discussion thread about the last /loadui repair:
http://www.eq2interface.com/forums/s...ead.php?t=3223