People used to buy out theaters to have that privilege on blockbuster opening nights.
Depending on the theater's manager, they'll either want someone to guarantee a minimum or to have a single fee paid up front.
There's nothing quite like knowing that everyone in the theater is a friend.
That said, you're 100% right about making an offer. Most theaters have underutilized screening rooms, and managers have the ability to rent for private events. I've done this a few times. The rental rate tends to be about 10-15x the price of a single ticket (in my experience).