The only company that have done that was ATLUS, but that's because they had a late entry. But even so, most of the games have the companies that are there but they let E3 show the games for them. If they are not there, E3 won't show them.
Tokyo Gameshow is more believable because Koei has been there and promoting multiple games. Ninja Gaiden in the past (2 and 3). DOA, NiOh, Dynasty Warriors/Samurai Warriors etc.