You might get some ideas by looking at some of the various flags of
Native American nations ... there are some shown on the web pages at:

http://users.aol.com/Donh523/navapage/

You might also try something like picking a major resource/symbol for
a tribe, like Melanie is doing a salmon stamp for the Salish tribe.
Most tribes have home pages on the web, you could see what types of
images or logos they've chosen to associate with there.

Rush Gatherer
aka Tara