The .380 revolver has existed for generations! IT's BRITISH!!!!
A dedicated revolver for the .380ACP?? (aka 9mm Kurz, 9mm Corto, etc.)
I don't see the point. Not that it isn't possible, but as others have mentioned not only does it face all the drawbacks of a rimless case in a revolver, but even a purpose built gun, made to get every advantage from the rather small difference in length vs. a 9mm, would find only a niche market, and a rather small niche, at that.
As to a top break, a number of the British .380s are. Webleys, & Enfields, mostly. .380 is the British designation of our .38 S&W round, although they load it differently than we do, generally.
Logic (and pride in 21st century engineering) says they should be able to make a top break in a powerful round, .357, or .44 Mag. One that stands up to the pressures. All just a matter of using the right steel and heat treating? I don't know, not my field of expertise. But if that's all it takes, why has no one done it?
With all the people I hear talking about how the S&W isn't "durable enough" for a lifetime of magnum shooting, I do wonder what they would say about a top break??