I am really intrigued by the bed runner idea. I figured they are just big table runners but didn't know how to figure the measurements, then found this blog.
http://hangingonbyaneedleandthread.b...explained.html
If for some reason you can't access it, the gal says The dimensions are typically 24" wide and the length is 25"-30" longer than the width of the mattress, so that there is a 12"-15" drop on each side of the bed."
I'm tempted to take my favorite easy table runner pattern, increase the size of the blocks, and make it to these dimensions to match my bed.