I've changed the editor (2.3.2) so, that i could change the toolbar without using a custom-configfile or predefine toolbars in fckeditor.js.
You just need to write something like this:
var editor = new FCKeditor("foo");
editor.Config.ToolbarSets = new Object();
editor.Config.ToolbarSets["my"] = [ ["Bold", "Italic"] ];
The trick is, that the created object needed to serialized.
So I wrote a little (un-)serializer.
The attached file contains these.
You need to replace FCKEditor/fckeditor.js and FCKEditor/editor/_source/internals/fckconfig.js
Just replace these files with the ones of the attached file or copy and paste the changes (diff is your friend :)).
Mention that you need to use the debug-version to work or just re-compress the project.
I hope it works for you.
Greetings from Germany,