I don't know of any documented accounts of lever guns, but there was a Sgt. at the Little Bighorn with a Sharps target rifle.
Pitspitr,
Yep, that is what the online article refers to. From that article, "Captain Thomas A. French of Company M carried a .50-caliber Springfield that his men called "Long Tom." Sergeant John Ryan, also of Company M, used a .45-caliber, 15-pound Sharps telescopic rifle, specially made for him. Private Henry A. Bailey of Company I had a preference for a Dexter Smith, breechloading, single-barreled shotgun"
I'll get over to the research library here on Quantico on Friday and see if I can find anything.