How permanent is scalp tattooing?
If it fades (like normal tattoos do) it would be difficult to work around the implants and have it redone.
Certainly one of the downfalls of transplants is its 'see-thru' appearance and tattooing could help, but only if the hairstyling was kept short & flat to the head.

This company offers the combination:
http://chicagopermanentcosmetics.com/Hai...lant.shtml
They say " Combination of the two procedures creates significantly enhanced appearance of hair density that can not be achieved by hair transplant alone and is particularly useful in cases when the number of follicles available for transplantation is limited."

Here is another company offering the combo:
http://www.vincihairclinic.com/scalppigm...epair.html

Here is a video of a transplant being used to disguise a scalp tattoo.
You can see the ink has turned blue.
http://youtu.be/RCNV5J83F7Y

and this one:
http://youtu.be/e-m9GcBAve4

The follow-up videos are here:
http://www.youtube.com/results?search_qu...g7QtyGMfvI

Here is someone who has blogged about having the both procedures:
http://fue-hairtransplant.blogspot.co.uk...micro.html

Talking of scalp tattoos, these are 2 of my all-time faves: