If Marvel doesn't own the rights than maybe it could be a movie released by 20th century fox like the upcoming potential Silver Surfer movie. It would be awesome to see a sci-fi space opera movie with travel to distant galaxies,space battles,alien planets and moons and halfmen/halfrobots flying across the starlit blackness of deep space accompied by the awesome legendary 20th century fox logo and cool fanfare. It would be reminiscent of a certain franchise set a long time ago in a galaxy far,far away...
Just because Marvel doesn't own the rights doesn't mean no one can still make a movie of Rom the Spaceknight. Maybe a studio like 20th century fox can make a Rom the Spaceknight movie in the next few years. I mean c'mon it would make an awesome space opera franchise as good as if not better than the original Star Wars trilogy or even Green Lantern.
Also Marvel or Fox should do a movie franchise with the Shi'ar Empire and/or the Starjammers. That would also make an awesome space opera franchise. But you would have to introduce them in an X-Men movie first since they started and were major characters in the X-Men comics. It's a wonder that they haven't been seen yet in an X-Men movie.