If it hasn't already been done, this one would primarily be for blacks.
But it would require a lasting material that looks, and feels like hair, and a thin transparent material that it can lay over. Ideally, these materials should last around 1-5 months. (it will be ideal if customers only have to purchase a new one every 3 months or so.
Also, a substance that is safe to use on the human scalp, and can be used to adhere the head covering to the human scalp.
The product would come as a sheet of hair, or something like that. Basically you would place it over your head, and get a barber, or someone else to cut off the excess, and line it up according to your head shape, and taste.
You would then either off your real hair, and apply the adhesive to your scalp, finally you would press your lined up head covering on to your head, and brush it or whatever.
It may look something like this, except the hair will be lower, and it will actually be lined up. and it should be sturdy enough to use for about 3 months hopefully.