You could try Fabricland, I understand they carry the basic colours of speaker cloth such as black or beige(possibly a couple of others too). You could also contact Solen(Montreal area) or StudioLab(Scarborough) or one of the several online speaker parts suppliers such as Parts Express.

Try your local Fabricland first, though, I've heard their grill cloth is very good(acoustically transparent).

Half of communication is listening. You can't listen with your mouth.