I don't know if Sun Bicycles (http://www.sunbicycles.com/) get imported to Canada, but their Atlas Cargo Trike has a capacity of 500 lbs (specs say 250 for the rider and 250 for cargo.

The Worksman PAV3 (a recumbent with scary-looking tiller steering that probably works great as long as you don't go too fast) has a 550 lb capacity. It probably also weighs 550 lbs.

The Worksman is likely to be indestructible, the perhaps Sun less so.

Worksman medium-duty executive trikes have a weight capacity of 300 lbs. http://worksmancycles.com/shopsite_s...ml/page13.html

Good luck.