A smaller R in .380 might be interesting, but what would be the advantage of a .380 that was the same size? Ammo is significantly more expensive, a bit less powerful, but the rounds aren't enough smaller to allow for higher capacity magazines.
If the entire gun was smaller, it might be worth checking out, but if the gun is going to be the same size and the barrels swappable, the only other caliber I'd be interested in would be .22lr, so I could plink cheaper with my carry gun.
This isn't meant to be a flame; it is a serious question. I doubt Rohrbaugh would make a .380 version if there wasn't a market for it, and I am probably just too dense to understand the why, so I'm asking in my ignorance for information... what is the advantage of .380 over 9mm?