My approach would be this; a national rent control board that sets maximum rents based on square footage, amenities, and average income in the area, paired with a crown corporation (or whatever you guys call it) that buys housing and rents it out.

The rent control board pushes rents down to a point where they're not more than, say, 20% of a typical single family income in the area, and when landlords call foul and offload all their "investment" properties, the crown corp scoops them up for cheap.

Finally, have the crown corp offer rent-to-own plans where you can buy out your house with the accumulated rent you've paid discounted from the price.

Oh, and of course slap on a vacant home tax so that landlords can't try to sabotage the system by just camping what they have while refusing to rent it out (most couldn't afford to do that anyway since their "investment" only works if someone else is paying for it).