Eaton's, the largest suburban department store in the provinces, was designed by Seattle's John Graham, Junior. The 4-level structure encompassed an astounding 362,900 square feet.
Photo from City of Toronto Archives / Series 249, File 199, Item 1.

Simpson's YORKDALE CENTRE store was designed by John Andrews. The 4-level store encompassed an impressive 285,000 square feet.
Drawing from John B. Parkin Associates