Well, she posted the last clue tonight... and wow, it's pretty! I'm glad I started the mystery. :)
I like to do things a bit different though, so I think I'm going to try my Christmas fabric version with some red sashing between the blocks:
It'll be the same 1½ inch strips that we cut for the rail fence and nine-patch blocks, so it'll fit right in. And I'll make my borders a bit smaller, so this quilt will finish at almost 76 inches square instead of 80, just a tad smaller. :)
Now I can't wait to get this all sewn together!