I believe there will be a hard copy of the game, yes, and concerning steam...

"The Steam client will be required for Sins of a Solar Empire: Rebellion for initial install, updates and Internet multiplayer, regardless of purchase location. You can choose to play in offline mode via the Steam client after initial install, though ICO features and achievements will no longer be available."

Straight from Yarlen.

EDIT: I'm a noob, and hijacking this thread. Who IS Yarlen, anyway? Is he like a public relations type employee of Stardock, or exactly? For some reason I'm imagining him like Pete Hines with a fake mustache and a sombrero. A couple minutes of searching, strangely, didn't get me an answer. If you know the answer for any other of the devs too, feel free to share.

I DID learn Frogboy and Yarlen both worked on Gal Civ 2, though, which makes me grin for some reason.

Yarlen seems to be the main developer from Stardock in charge of Sins. You'll notice he's the one posting the change logs and has a Stardock employee under his picture when he posts. He's also the only on besides Blair Fraser and Frogboy (the CEOs of Ironclad and Stardock) giving interviews with the media.

Use steam or else..

don't listen to the propaganda campaign about steam sucking.

don't be a victim of peer pressure

don't be poisoned by the media.

Actually I could start Rebellion with steam offline without a problem...?