We stayed at a condominium at Sinchon area that we booked via Airbnb. It is a loft-type unit and has bathroom, kitchen, living room and one room at the 2nd floor. The place has 4 beds but it can fit 7-8 people comfortably with the pull out beds. If you’re planning to stay at Sinchon area, I definitely recommend this place.
I currently can’t find the exact listing of this place at the Airbnb site, but this one is similar. The one I linked might be in the same building as the once we had booked, but ours was a corner unit so it might seem more spacious. I hope this helps!
View from the condominium unit