High number of unsold units in construction phase pose 'elevated' risk to economy.
Proximity to transit now driving decisions about home purchase and office development, report says.
Bank warns household debt also a hazard.
Overvalued housing markets in several Canadian cities and high household debt poses a "clear and present danger" to Canada’s economy, TD Bank warned in a report Friday.
Federal Finance Minister Jim Flaherty says changes at Canada's banks are cooling off Toronto's condominium market and he expects Vancouver's market will soon follow.