Metroid Fusion probably isn't the best place to learn about the joke, since there are no epomynous Metroids in that game (the last one was killed off in Super). The Space Pirate quote there was from the Prime series, which occurred between the original Metroid and Metroid II, which was a period in which the Metroids were still alive (but god I wish they weren't... they're insanely hard to kill).
And the unibody MBs are nice, though I'd save up the extra $100 and get a 13" MBP.