The bik Titantrons are actually the ones you unlock in the WWEShop section. The actual entrance videos are xmv files. Also, the entrance music is contained in the sound\streamed\MusicSet*.xwb files. I'm not 100% sure how to get these out yet, but they are Xbox WAV files. If you check the cache on your Xbox drive after a match, you'll see the uncompressed WAV files of the wrestlers you used. What is really lame is that they included the crowd noise over the music. The format of the files is entrance_*.wav where * is the name of the wrestler "entrance_cena.wav", etc. Another item of interest is that the Create a Belt data seems to be inside of CAB\Textures, and all of the files are TIF files that open up in Photoshop, etc.
If there is a tool that can extract the xwb's to their native WAV files, and then place them back, we can easily edit the pre-existing entrance music. So far, the tool I've found extracts them to some adpcm format, which i cant make any use of.