I should have been less glib in my post. I live in a Japanese farm house. The tatami is the woven straw kind made for living spaces. There is no covering, so any abrasion is going to tear up the mat. I am going through the same thing as you and looked into the tatami made for Judo sold here. The cheapest ones start at 30,000 yen, almost 300 bucks a piece. We finally decided to rent space/time at a local junior high school which has a Judo dojo. However, I have a good bit of farm land and am thinking of building a stand-alone dojo in the future. Right now I am thinking of doing the canvas covered floor. I am glad you are going through it first so I can steal your experience/ideas.