Not every location is gorgeous; not every location even offers a good background for portraits; in fact, more often than not, location photographers have to work hard to make something out of nothing. I recently found myself in that situation while shooting portraits for a financial client in lower Manhattan. The first challenge was only being allowed to shoot in a small corner of the office lobby; it was very limited. But with a little ingenuity and by moving some furniture, I was able to find an angle that used the space outside of my restricted area. I was able to stay where they wanted me to, but by using the lobby itself as the background I could get the look I wanted without taking up too much room. Yes, it was tight quarters for shooting, but in the end, the final shot is all that matters.
Limited space doesn't have to mean limiting your portrait options. I loved the way the light was streaming through the window in the background and used that as an element to offset my subject. ISO 50, 85mm lens f2.8 at 1/60th sec.