Stuart, I've heard that the Jackson County Historical Society has quite a bit of first-hand information about the Jackson Guards -- Private Bevans' outfit -- some of which has been published in its "Stream of History" quarterly. Here's a mailing address from the Jackson County USGebWeb site --

Jackson County Historical Society
c/o Wayne Boyce
7 Pickens Street
Newport, Arkansas 72112

I posted a Shiloh casualty list from the 1st Arkansas on this message board some time ago. It might still be archived; if not, and you'd like me to re-post, just let me know.