Personally, I'd like a name that is more than just Starships. I was looking for a Space adaptation of BRP in general and thought, "Oh maybe they'll have some starship based info here, but I still need MODERN rules too." Lo and behold, they're in here too. BRP Space would be a fine name for me. I have Star Hero, GURPs Space and a few others. I don't judge one book by another's name. :-)
As for breaking the different sections out or making it one "book". I'd go for one book. If you have more ideas later, then put them out as suppliments.
James / Nezeray