I do it all the time then design corner blocks that join the borders, like a partial log cabin block. I quilt the body of the quilt without borders, then add the border section, batting and backing and quilt the borders. I'm diong the quilting on my dsm, so this works because it reduced the size of the quilt that you have to manhandle. This is how I did my avatar. Can you tell that the bottom corners are separate blocks?