Started a similar one a while back and didn't gain too much ground, more specifically about native-themed tattoos. http://www.lastsparrowtattoo.com/forum/tattoo-designs-books-flash/1845-native-american-tattoos-designs.html It's an interesting thing because -- let's take the example of a lady head in a headdress -- most people just throw a bunch of designs together and put a headdress on a sexy-lookin' lady, which is obviously not accurate. But that design, as well as many others, have become part of the tattoo vocabulary and it seems there are plenty of native people who have no problem with it.
I've actually been thinking about this lately, too, and would love to talk to someone like John Gloyne over at Hot Stuff in Asheville, who is a great tattooer and also Cherokee.. maybe do a little interview kinda deal.
Anyway @cltattooing had the best answer.