If by themes you mean the player symbols then yes you can. You have to make a mod to do this though. The pictures themselves are located in the RaceLogos.tga file in the textures folder, so make a copy of that and make your new themes in there (notice how the original ones were made). You also need to edit some of the files in the window folder that you can edit in notepad but I don't remember which ones at the moment.
