This site shows you how to make the D9P I Spy. I think it's great.
http://obsessivelystitching.blogspot...ring-nine.html
Also, if you go to the top of the page you can search I spy quilts here on the board. Everything from photos to ideas to sizes to a tutorial. You can use any size blocks you want and make it as large or small as you want depending on the what you think the appropriate size is for the person who will receive it.
I always use 5" squares from the swaps here on the board. Mine are usually about 40-45" wide and 50-55" long as I make them for toddlers mostly.