Both models below are from Shapeways. The saucer sections on both are roughly the size of the Constitution CA (USS Enterprise) saucer on the MicroMachines miniature. That's about 4cm's across. The length of both miniatures is also the same at just over 7cm's. Unfortunately I can't find them on Shapeways any more, so I can't post the link to them.
The Deneb Class Frigate
The Akula Class Destroyer
