I've finished my granny square lap blanket...
The edging is some blend of Knitpicks cotton, I got it at a sale without a ball band, and the rest is varying shades of Knitpicks Shine Sport Yarn.
The edging is my own pattern and can be found in my pages up above or HERE.
When I was starting to run out of yarn I did several rows back and forth along the top and bottom for extra length before I edged it with green. I even blocked this with a light misting of water which seemed to help open up the blanket a bit.