Brass would be nice . It shouldn't really be to hard , some AM companies make single 50 cal brass cases and the disintegrating link belt in 1/35 . I'm sure Sherman 75mm and German Flak 88 rounds in 1/56 would be larger than those , hence easier to make . Lots of bits made in photo etch , turned brass and resin for the 1/72 - 1/48 model plane guys as well . The big question is , how many of us would likely buy this stuff to make it worth someones while ( $$$ ) to produce it ?