These 15 wards are the most logical ~184 sqkm/71 sqmi I can come up with for Toronto (population is 823,140).
http://www1.toronto.ca/wps/portal/co...0071d60f89RCRD
It includes the established hipster neighbourhoods along Queen West and College; current trendy spots of Parkdale, the Junction, Brockton Village, and Bloordale; revitalized warehouse districts; working class/ethnic urban hoods yet to be touched by gentrification like Weston, Mimico, and the areas along the St. Clair and Eglinton corridors; it's got an Eastern European enclave on the water; there are large Italian & black populations throughout, and Jews along Bathurst; some of the city's most deprived sections at its edge; and a generally dense, mostly low-rise housing stock in the older parts. Unlike Brooklyn however, about half the area is post-war development, including sprawling industrial zones. It's also completely different in just about every other meaningful way.
This thread just doesn't work quite as well or as equally across cities as the "Manhattan" one (inner-most 23 sqmi) does.