If the fleet does exist, it would no doubt be owned by Darkness (ie: the combine itself) and would be more used for flavor then anything else.
That's part of the fun of the game, there is always something new being added, and with such an immense universe to work with, the admins have plenty of space to hide stuff for the players to find.
I've also heard rumors from back in the old days of a wreaked Death Star being tucked away in some hidden system. Will it have any impact on game play? No, would stumbling across something like that be a sweet discovery? Definetly.
I do know the admins have hidden some such items before, for example there was not to long ago a system filled with the wreaks of nearly every type of ship in the database. Uterly useless to actual game play, but still very nice to see in the scanner.
Whether it still exists or not I'll let you discover for yourself.