>Hydragyrum? I don't think we've seen that ship on screen before... or
Yes, we have. Len's been using it all Fulcrum, for one. Gryphon explains in the annotations that Naboo has 3 royal transports, Mercury which is the big XB-47 looking model that gets blown up at the start of Clones; Quicksilver (?not sure, proboboly wrong?) That is the more SR-71 looking ship from Phantom Menace, and then Hydragyrum, which appears in the later half of Sith.