Doctor,
I dont know if you know this, but when scalp hair is transplanted to the body......................it grows short like body hair
Body hair transplanted to the scalp has been documented to grow over six inches in length. However, it does not always do this. There are alot of men who get body hair transplanted to their heads now, and a few docs specialize in this.
Here is a pic of a guy who moved only body hair to his head
http://www.dermhairclinic.com/photogallery01.html
There are problems with body hair though. .................it does not always lengthen its cycles, and some patients have to keep cutting their hair short. Its also prone to staying kinda "kinky" and not straight like head hair. Also, transplanting a good densities sees lousy yields in most cases. Its been found that 30 hairs per square centimeter (which isnt very thick at all) is where the most hair will actually grow.
However, there has been one "wow" case with bodyhair, but I cant post the pic until Cole (a Doctor) updates his forum. A guy who was Norwood 2 with diffuse thinning literally got a Brad Pitt (hell, even better than that) hairline of super-thick large straight BLACK hair. It looks incredible.
BHT's as they are called often take two or three years to "grow in" also. They are very contriversial. Most, in my opinion, have been failures, but there has been some good results. Oddly enough, the best result I ever saw was in a guy who started finas and minoxidil.
I have a feeling lots of ageing in the scalp and collagen restricts BHT's. ALso the BHT's are usually one and two hair units, not the two's-through fours' we see in scalp hair donor area follicular units.
One more thing, if you move scalp hari to the body, alot of it wont grow immediately. The shorter growth cycles seem to take place immediately. There was a Korean study to this effect. The hairs to stay large and fat though and keep their original color. Much of this is attributed to some skin hormone that had a ridiculously long name 3 hydrodoxy-blah-blah-blah.............................