That's one for liking the ideas. Any others?

Yes, but not every Indian Nation. Some are small and struggling. Some haven't been recognized as a nation yet. With a little research, I'm sure we could even find a new nation that the denizens didn't know existed prior. All the tribe would need is a name.

FTFY

I'm a native.All you white wetback illegal immigrants need to stay out of our business. If we wanted a currency we would have a currency. At this point we're content to run you into the ground financially with our casinos you just can't seem to stay out of.

carry on.

I would think that there would be provisions in any treaty that would prevent this from happening, I'll do some research and see if there are any prohibitions regarding it.

Its very interesting, some reservations ( at least in canada ) control large amounts of lands with potential mineral development, not to mention lumber. Could a cabal of reservations join together to back their own currency with the natural resources as a backing?

Hi, Lakota Nation really already has one, see these links :

http://freelakotabank.com/currency.php

Lakota Nation : http://www.lakotafreedom.com/

See this ( http://en.wikipedia.org/wiki/United_States_v._Sioux_Nation_of_Indians ) 

Maybe they will convert their currency to and from BTC, who can convince them?