Here is the opinion of the Tenth Circuit sitting en banc. Five judges dissented. [Updated link here.]
Here are the en banc supplemental briefs:
Navajo Nation Supplemental Brief
American Indian Law Profs Amicus Brief [The court denied the motion to file this amicus brief. See opinion at 25 n. 7]
Our posting on the panel decision is here.

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tenth circuit opinion can now be found at:
http://www.ca10.uscourts.gov/opinions/07/07-9506.pdf