The MCU fan page on facebook made an interesting observation about the starships in the background looking like the design on Nova's helmet. Could this be a hint that he makes a cameo?
Venom, your post generates a good question for comic-fandom. What are those ships or sattelites behind the Guardians?
In the Silver Surfer cartoon, Thanos pilots a similar ship. However, those ships are probably not his, for they are not attacking anyone.
They could be Xandarian Nova Corps as you suggest. After all, Marvel did attempt recently to re-acquire Galactus for some reason. In the comics, Galactus destroys the homeworld of the Luphomoids. In turn, the Luphomoids invade Xandar to grab new territory. In turn, the Nova Corps opposes the Luphomoids. So, Galactus, the Luphomoids, and the Nova Corps could all appear in the new Guardians of the Galaxy movie. Marvel is giving people enough reason to at least start an internet rumor ;)
My opinion: I highly doubt it, but it would be SSSOOOOO AWESOME.