hubcap - there are a couple I am familiar with: the 38-45, the 40-45 (aka 400 Corbon). I would love to add the 45 GAP (Glock round) in there, but it's still a 45 caliber; but maybe we can add the 460 Rowland or whoever and the 45 Super, all 45 cases just different loadings and power ranges.
I don't know if anyone has necked down the 45 to take a 44 slug (maybe) or a 41 slug, or anything smaller than the 38 from the 38-45. Maybe someone else does..... HTH. Mikey.