The only Remington Rolling Block rifles currently (or recently) in production are the limited Remington Arms rolling block rifles in BPCR calibers and the ones by Pedersoli of Italy. Lone Star in Texas also makes them on a custom basis. Navy Arms imported some Italian rolling block rifles,pistols, and carbines. Star (Spain) used to make carbines in .30-30 and .44 magnum calibers.
I can't see any major manufacturer getting into production of a repro 1866 Springfield or Military Rolling Blocks because of the very limited market demand, plus the considerable product liability issues of making and selling reproductions of 140 year old rifle designs that can chamber and fire modern smokeless cartridges.