When I read this last night, all I could think of was that you'd have to figure out how to get a nice mitered edge--so the corners of your border would meet at 45 degree angles.
But then, it occured to me that you could pick up stitches along the top of each square and knit a border, then along the bottom and knit a border.
Then you could pick up stitches all along the each side, from the top you added on, along the square, and down to the bottom of where you added on and knit out from there. Your stitches would be going in opposite directions, but that could look really cool.
Just an idea. This is the kind of thing that I think of after I turn out the lights. :rollseyes: No wonder I'm tired.