At the Puyallup, WA Quilting, Sewing and Craft Expo that I went to last week, a woman was demonstrating a presser foot that would machine sew the binding (with monofilament thread and a tiny zig-zag stitch) and claimed one of her quilts was submitted as a great example of hand-stitched binding. It was very hard to tell as it used the monofilament (invisible) thread, but it looked very nice. I happen to enjoy the hand stitching, so wouldn't spend the money. Unfortunately, I didn't get the name of the foot to tell you.
I'd go ahead and enter your quilts with machine binding and see what reaction you get. I think the more of them that are entered that way, the more acceptance will be generated.