Overmountain Press

I've only read one book published by this primarily Appalachian history press (William Garrett Piston's Carter's Raid) but was favorably disposed toward my single foray. Piston, probably best known for his Longstreet bio and his Wilson's Creek study in partnership with Richard Hatcher, is a good historian so it's no surprise. The Overmountain Press website lists the following titles from the Civil War section of its catalog:

Civil War History:
History of the Fourth Tennessee Cavalry
History of the 13th Regiment Tennessee Volunteer Cavalry
History of the First Regiment of the Tennessee Volunteer Cavalry
East Tennessee and the Civil War
Miss Nan: Beloved Rebel
The Loyal Mountaineers of Tennessee
Voices from Cemetery Hill
Jack May’s War
The Bridge Burners
Thrilling Adventures of Daniel Ellis
Carter’s Raid
Sisters of Providence

Just click on the Civil War History link for access to each book's webpage. Brett Schulte, who is looking for regimentals at the moment, might be interested in the first three titles listed (although I can't personally vouch for their quality). I am a bit intrigued by Jack May's War.