I didn't think these would be environmentally good for our landscape and hence difficult to find. Or are you referring to those recycled tire materials that are sold in sheets or mats? Similar to the ones used in playgrounds.

No, I need rolls of black plastic material used to grow heat-loving vegetables in Northern climates.
Similar to the picture below:
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Picture source: http://greenfusestock.photoshelter.com
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If somebody needs it - found it today in the Humber Nursery in Brampton. They sell black plastic sheets (already perforated) for vegetable gardens 15m x 1.5 m for around $11 each

Have you tried Lowes? I dimly recall seeing black sheets in their are but call first. Also call Angelo's Garden Centre in Vaughan as well. I suspect based on your zone and the reference to Sheridans that these places may be closer to your location than Humber Nursery. But I have to say, I do love Humber Nursery for the wide number of products they carry.

Also call TSC stores around the area. They carry farm products but do call first.