I have created a mod will allow you to have the old look and feel with any custom mods that you like without having to maintain the xml files for any windows you haven't modded.
For example lets say you use a custom player and group window and want the old look and feel.
Currently you would have to use a copy of default_old with your modded player and group windows. The problem with this is that the default_old is nolonger being maintained so any new features SoE adds won't appear even in the non-modded windows.
However if you download and use the 'old look and feel' mod with your modded player and group windows then you will not have the above problem as the only files you will have to update are your modded ones.
You can download the mod from this page http://maddave.dnateam.com/everquest/everquest.html