I started to address this topic in another thread, but figured it deserved its own...
Rohrbaugh will be building an R-380 (although I am not sure if that will be the name). The .380 will be the same size and weight--in fact the only real differences are the magazine, barrel and a few tweaks here and there.
The first question you might ask is -- Why? I had the same question. Now I know.
One reasons is that the .380 will be a natural for export. Many foreign countries do not permit civilians to own guns in "military" calibers like 9mm.
However, the .380 is a very viable gun for the U.S. as well. If you think about it, most .380s are blow-back types rather than locked breech. As a result, the recoil -- even in a larger sized gun like a Bersa Thunder -- is noticeable. The locked breech Rohrbaugh .380 will be much nicer to shoot than other similar sized .380s and far nicer than the R-9.
How much nicer? From personal experience, I can say A LOT. Here is a picture of a prototype Rohrbaugh .380:

And here is pic of me shooting it at the factory!

This thing has an amazingly light recoil. Anyone who is recoil shy or doesn't think they can master the R-9 needs to try one of these when they become available.
I don't know what the time frame may be -- obviously they are busy right now...

What do you guys think of a .380?