My 12-year-old daughter had a very small private room at a hostel in Victoria, BC. I think it probably used to be a walk-in closet, or possibly a bathroom. She had a twin futon that was just slightly less wide than the room. There was maybe two feet at the end of the futon. So maybe this is about 4' x 8'? It also had a sink, refrigerator, and window. It really was not bad, just small.

The funny thing was that I had reserved this thinking we could both sleep there. However, when I saw the room I decided she would get it and I would sleep in the adjoining dorm. That worked fine.

An Ibis hotel room my son and I had in Gothenburg, Sweden was maybe 8 x 10, plus the bathroom and a bit of a lead-in hallway. I had a double bed, and he had a bunk that jutted out of the wall. But it was beautifully done up, and the hotel was a moored boat, and there were gorgeous views of the river.

We had a hostel room in Aarhus that had two twin beds, just enough space to walk between them, and not much space at either end of the bed. So maybe that would be 8 x 10 also? There was the short lead-in hallway and a bathroom, though. This place had the feature of loud horns going off in the middle of the night (it was near the railroad tracks and the harbor). I can't say my sleep was seriously affected, though, as I had jet lag. It did not wake me up.

These are the smallest rooms I've seen, and I don't consider small rooms bad. Actually if I get out alive in the morning without insect or rodent contact and without my sleep being disturbed, I consider that a victory. So far, I am batting 100% in this category, despite my cheap tendencies.