At the last All Day Sew, I dug in my "good trash" and pulled out a bunch of fabrics. Some of my quilting friends looked uhhhhhh doubtful. They will see, next time we meet. Here are some of the panels, or blocks. Any size will do, any colors, but I kept the pieces mostly square or rectangular.
My letters are 4 inches, and after a review of Steam-a-Seam 2, this is the draft product.
The borders will be reduced as needed, land I'll do a blanket stitch around the letters. Then I'll layer it with batting and do a little machine quilting around the letters. I'll sew little triangles into the binding at the corners and insert a small dowel or paint stick for hanging. I've made this before and it turned out very well! Just think of all the phrases you could use! A kids name, "Gone Quiltin'", "Quilt Room", "My Space", "Happy Birthday", etc.
Because I am placing my cardboard letters on the back, sometimes the result from the front might not be exactly what is planned. Seams might not be where you wanted them, but you can always make another letter if needed.