I really like your brain kaboom line and I want to borrow it! You are not alone. Here is what I do when these fabric fits occur. I just get started and let the quilt go where it goes. It will become as big as my fabric lets it become and then I add a few borders if I want it bigger. Sometimes they end up being a wall hanging and sometimes a big quilt. Just use that beautiful fabric and what ever grows from your piecing will be beautiful too.
By the way, you can make logs as wide as you want in a log cabin so if 2 of 2 1/2" works for you, go for it!
I also like that nine patch you linked to.
peace