Icelandic sheepskin cut into small (scalp sized) pieces works really well..... and it comes in different natural colors.... unfortunatly, it's not really long enough for an ex-longhaired person....
I've made them for Monster costumes.... but painting on a layer of fake blood, and letting it stain the flesh side works well, most of the fake blood flakes off when it's dry, but it may be "over-kill" if you want them to look realistic instead of scarry.... but you can test a chunk of scrap first wipping off the fake blood to get the amount of staining you want....
A few scalps, some fake fingers.... lots of fun for an Orc or Reaver costume.... But the scalps do look real......