It is amazing how many Civil War buffs are into this battle. I used to know the late Brian Pohanka and he was deeply into the Indian wars as well as the Zulu wars of southern Africa (as am I). Blue & Gray magazine did a Little Big Horn issue a while back and I have encouraged Dave Roth, the publisher, to do more of the pre and post-Civil War Indian engagements where Civil War people were involved.
Two great books to cover this topic are by Robert Utley, "Frontier Regulars" and "Frontiersmen In Blue." Paul Hutton is also an excellent historian of this era.
Greg Biggs