Which style transition/threshold do I need for carpeted stairs to meet floor boards?
My recommendation would be to terminate the carpet on the last riser.  If you put in a threshold, yes you'll protect the end of the carpet, but you'll still have a lip for people to trip over and fall.  Not fun.  

If your flooring has no terminal piece at the top of the stairs, you can certainly get pre-shaped "noses" with proper support built into the shape.