I've never seen them, but it's quite easy to print your own repetitive design. You can use foam rubber, or a potato! Carve a bas-relief of whatever you would like to print, and use a dye or ink made for fabric, that won't bleed when put through the wash. Soft cotton jersey sheets are quite inexpensive, and easy to work with.
Fabric Stamping or Fabric Printing: An Alternative to Fabric Painting