I married a woman who was raised on the Crow reservation. Her and her brother were mostly white, but they were members of the tribe. Interestingly, at the time we married, I was a Cavalry Scout with the US Army (19D secondary MOS, 11B primary). Anyways, stories still pervade that culture. Everybody knows what it takes to become a war chief. I believe there will be another in the future at some point. The circumstances get more difficult to fulfill, but I do think there will be another one day. Also interesting is the "generally known, accepted fact" of Custer having been killed while wading through the river by himself and with one other soldier (bearing the standard), apparently leading the charge into the village. He did not die on the hill. Also, it's told that he was mighty drunk when that happened.
1/4 blood quota is what most tribes require to be tribal members. If you have children, its worth the effort to make sure the kids are listed by the tribe even if they don't make the blood quota. Some schools get extra money on decedents for certain programs.
I believe for the Crow tribe, it's 1/8 blood to enroll. If I had had children with my ex-wife, our kids would have been able to enroll, and I would have enrolled them. You're absolutely right, that there are some good benefits to being enrolled in a tribe.
Interesting, the Chippewa go with the 1/4 rule, and I'm 1/8 so I got all the "fun" of the Rez and not much of the upside. Plus, it was a Dakota rez instead of home country. Sorry it didn't work out.