I'm not sure how I missed this, thanks to Tiny Solitary Soldiers for posting about this!
Battlestations is an on-board skirmish game (in 15mm no less!) that depicts boarding actions in outerspace and also ship to ship combat. The back drop is more of a space opera setting rather than hard sci-fi, but that's a plus in my book. The miniatures are decent, but the human figures are a bit too cartoony for my taste. This would probably be a decent system to use with Star Frontiers or Space Opera. Plus there's a scenario book for you Lovecraft fans called Deep Ones In Deep Space!