Furniture and Furnishings - Fitting sofa into basement

In the process of finishing my rec room in the basement. Due to the location of two support beams, its only going to be leaving me a 31 inch finished opening to the rec room without a door. My stairs also turn half way(can't think of the proper term). What are my options for getting some sort of sofa down here? Most sofas seem to be 34 or 36 inches in depth and height. I know the pillows squeeze down on lots of them, but its way too much work to buy a sofa, haul it here, and then get stuck finding out I need 1/4" more.

Are there any sort of sofas out there that can be assembled, like from IKEA or should I concentrate my efforts on finding a sofa with measurements(probably limited) that will fit.

Google for 'ready to assemble sofas.' Finding small scale furniture can be a challenge.