This highly-rated treadmill from Urevo has a versatile two-in-one design: With the frame up, you can run up to 7.6 mph, and with the frame down, you can tuck it under your desk to walk up to 3.8 mph.
Space might be limited if traveling somewhere and staying more than overnight or a day or two. Wear your running or workout sneakers when traveling to save more space than dress shoes. Bring ...