Cyril Borovsky purchased a 16-foot wide strip of property in Toronto. Then he built a 3 bedroom, 3 bath, four-story house. Borovsky says his design approach could be used to turn parking spaces into homes. You could also buy Borovsky's house for $3 million.
More here: 154 Hamilton Street
And other impressively slender Toronto homes: "Three buyers who found narrow plots of prime real estate and made it work" (Toronto Life)