Look for other calibers maybe... but not 9mm +P.
Speaking for myself, I don't see a need for the R9 in a different caliber. I understand that a .380ACP version might sell in countries that do not allow citizens to own military ammo but that is not the case here and I can't see myself carrying a .380 when a 9mm in the same size package is availabe.
The only other caliber that would make sense would be the .40S&W but, again, for me, that wouldn't be an option. I tried the MK40 and found it to be too much of a handful -- too much recoil and too little to hang on to. An R9 in that caliber would be even worse -- smaller & lighter than the MK40 would give it a mucher greater kick. Might be good for some folks but not for me.
A +P gun would be a totally different gun.
I would like to see a slightly larger version of the R9 rated for +P. Maybe something the size of the now discontinued Colt Pocket Nine.
In order for Rohrbaugh to grow, they have to go after more than one market segment. They already have the smallest & lightest 9mm gun currently in production. Price, however, is keeping it from selling like hotcakes. Consequentially, they need to expand in other areas. Other calibers is one way to go. A slightly larger and more beef'ed up version of the R9 designed to handle +P ammo is another way to go.