With a room that size, I’d be putting in a projector with a big ol’ screen and two rows of seats. You can always suspend the surround backs anywhere you’d like. I think for optimal sound from the SB’s, you want them AT LEAST 6 feet behind the back seats. Heck, you’d still have enough room for a pool table.

For sub, I’d go with two EP 500’s, or preferably, two EP 600’s.