I have an unrealized idea to make such a helmet and jacket holder. But I don’t store anything like a helmet or a coat hanger above my tank/paint work. I found that helmet manufacturers don’t want anything touching the helmet insides except your noggin, and even then you’re advised to replace it at some interval, 5years? There is a compressible layer/liner in there to reduce transmitted impacts. So my past practice of hanging my helmet on my mirror and fastening the strap so it doesn’t fall is not acceptable.
A shelf might be the best, and you have to keep the helmet secure. So it doesn’t get knocked off or dropped.