You can create a šleeping area almost anywhere BUT toilets need to be plentiful and easy for everyone to access.

toilets need to be...easy for everyone to access

Indeed!

Considering that many people didn't have a single flush toilet until after WWII and they managed --I am not sure how much space I would allot to toilets in a house like this.

That's pretty awesome! I agree that with less than 500 sq ft, it's no surprise that there's only one toilet. This is a house designed for adults, not children, but there are no shortage of adults (singles or couples) looking for a unique house. The biggest downside is the low ceilings, I think.

My sister and brother each lived in 13' wide houses at different points in their lives, though they were semi-detached (unlike this one).

There are some 9 foot houses here and 11 wide is pretty common. I am not sure if an empty 9' lot is buildable at this time.

Agreed, they did a great job utilizing space. I LOVE this house, I've walked by it many times. I'm a bit surprised a family with kids bought it... but it's a prime location, a single family with a yard & roof-deck -- not easy to find in the city. The North End is a beautiful, historic neighborhood, they just built a brand new state-of-the-art elementary school, it's right on the waterfront, the financial district is a 5-minute walk. If I had an extra $1.25M, i'd have bought it :-)

The overall square footage is 1165, which is not that small. It's helped by passage down the side which allows for lots of windows which creates more legal bedroom space.

palimpsest - It's 1165 SF total... spread across 4 floors, the footprint is tiny, but you're right, it's a decent size for a 2-bdrm.

Yes I did a typo. 1165. My former neighbors live in 1150 and are a family of 6. Luckily the four kids are the same gender. I realize that is tight, but people do it.

The overall square footage is 1165

Ooops, I did misread the listing, sorry.