I believe that Border Creek Station packages and sells the pattern for their mystery quilts well after the mystery is over. The mystery quilt is something you sign up for through your local shop if they are participating or through a shop that is willing to mail the instalments monthly. I checked their website and saw at least one past mystery quilt available as a pattern.
Our reveal party is in 2 weeks so I am trying hard to get this done. Sign ups are going on now for the new mystery, I am still thinking about it.