Don't know about Toronto. If BC (Vancouver), I would use
www.rentbc.com for short term furnished housing
Furthermore, in the summer seasons, you can always check with colleges and universities in your destination city whether they have available accomodation.
Steaky, if one wants temporary accommodations, furnished, then
www.rentbc.com is not very helpful. It lists mainly one-year leases. I even emailed a property manager of one of the listings, a manager in charge of (they say) 100's of properties, and they "promised" to get back to me if they find any one-month leases. I am not holding my breath.
So, we're still waiting for a practical, useful way to find short-term accommodation in Canada.