[Windborne]

The nomad race is certainly different from the pirate idea because they have the chance to win, special facilities that make SPACE itself their home planet, things like being able to mine nebulae, research centers on ships, population that lives and grows on ships, etc . .

However the pirate race could easilly be a nomadic MINOR race option, limited to only maintaining a small fleet of their own ships and a larger fleet of captured vessels, limited in how much they could mine/refine themselves, etc . . . This would lead to a situation where the small pirate fleet couldn't support all it's ships/troops without tribute and plunder from other races.