I don't think you can trademark at title
per se if the property it is connected with doesn't exist in concrete form. The reason the cat was let out of the bag for the Lucasfilm stuff is that the company registered the internet
domain names for "Attack of the Clones", etc., so that no one could beat them to it. (Years ago a guy I know slightly registered the domains "www.starwarsdvd.com", "empirestrikesbackdvd.com", "anewhopedvd.com" and "returnofthejedidvd.com". He wasn't a cyber squatter, and had no intention of charging Lucasfilm big bucks - or
any bucks - or the names, he just wanted to be the first to know when the DVDs were on the horizon. He registered the domain names as a kind of trip-wire because he figured he'd hear from them when
they tried to register the names and discovered he owned them. He heard from them all right - he heard from Lucas's lawyers back in 1998 and was threatened with all sorts of nastiness if he didn't relinquish the names - which were based on trademarked items - forthwith. He complied.
)
I suppose one could do a search at the patent and trademark office for filings under
B5, but at I doubt there would be any reason for WB to try to trademark whatever "TMoS" means.
B5 itself is already trademarked, so the subtitle probably doesn't have to be. (Oh, and in reference to another post - if the "o" in "TMoS" stood for "Original" it would be capitalized. Since it is lowercase it can only stand for something like "of", "or", "on", etc. Since JMS has been so careful and consistent in the way he types the initials, we can be quite sure that he's following the usual conventions for capitalization in titles.)
Regards,
Joe