I'd like to see a downloaded "Battle rifle" class. IE a 2 gun class, but using documented milspec weapons, 1866-1900. Trapdoors, Spencers, Martini Henrys, Sniders, Krags, Lee-Metfords/Enfield Mk 1s, M1888 Mausers, etc. Must be "Rifle" caliber, but using low velocity lead bullet loads to avoid target damage. Uniforms to match the weapons. Don't show up for the Rough Riders with a Mauser.
My only provision would be no stripper clips. A simple tecnical limitation, easily enforced. I'd like to eliminate Mauser 98s, but I suspect they're too popular. Want to use that 98 with your picklehaube? Fine, no stripper clips. Divide them per NCOWs rules, IE powder and handgun style.