It's my understanding Sharps didn't offer cases, so if there are any around they were either a very special custom made case, or an owner built case. Some dealers made cases at customer's request, but doubt they'd have a Sharps Rifle Co. label. A label isn't tough to fabricate today using the letterhead as a basis to build it.
Marlin also never made factory cases, but I've built several for my Ballard, and Marlin rifles. I used Marlin catalog images of their logo, and simply copied, and blew them up to the size I wanted, and glued them inside the lid of the cases.
