The company is called Skip Stitch, and it sells the rotary blades to make holes in fleece.
I went to this website
http://www.skipstitch.com/ and ordered the speciality blade for my 45 mm rotary cutter.
The blade makes tiny holes that are evenly spaced apart. The website has a little video with instructions.
Another board member told me that these blades are also available from the Project Linus website.