The center panel on the front is a nylon flag from our local low-cost imports shop. I was a little worried about using the nylon, but it has turned out well. I backed the nylon panel with solid white cotton, the kind I often use for backings, so even if it gets tugged about and the stitches snag the nylon I won't worry about the batting bearding through.
The finished piece is slightly smaller than a standard twin size, as it's for a top bunk, measuring 50" wide x 80" long:
You can find out more about this pattern on my Craftsy page, here.