Recycled.ca
These are 100% recycled shirts offered in ash grey and white in bulk only.
eco-gear.ca
100% recycled tees as well as other eco items, with charities attached to sales.
I'm looking into using their shirts for my own designs, but at the moment it appears they only offer shirts printed with their own graphics. I will update whether they offer blanks later.
Recycled tee list
This is a link to a site that does an overvue of recycled clothing methods being used and info on the options