As a corporate location photographer in New York City, I shoot a lot of portraits in offices all over town; I've worked in some of the biggest penthouse offices you can imagine and then last week, I worked in the smallest space I've ever had to use for shooting portraits. No joke, the tiny conference room was probably 6'x10'. And you know what? I still shot some nice images.
The big downtown financial firm needed some new portraits of key advisers to update the company website and use as LinkedIn profiles but they forgot to book a space for me; luckily, this tiny conference room had a window facing the hallway, which gave me 4 more feet to use as a background. I knew no one would believe me about the size of the space so I took a shot from the hallway looking in the door.
In the end, it doesn't matter how cramped or uncomfortable you are taking the picture, even if it means squeezing a 6'4", 225 lbs man into a tiny corner; all that matters is the results.