Here is a link that shows them side by side...definitely not within 0.1" of each other:
http://www.rohrbaughforum.com/YaBB.cgi?board=Other;action=display;num=1315952529;start=0#0
I've shot plenty of +P out of mine, so I don't see a reason for it.
Arne must have changed the grip to make it bit longer. That's really the only difference. The Boberg is the same length as the Rohrbaugh, 0.1 inch thicker and judging by the picture, 0.25" taller. It is right there with it as far as size goes. I can tell you Rohrbaugh is very adamant about not shooting +P ammo. Even if you do shoot +P ammo, the energy and muzzle velocity you get out of it isn't going to be anywhere near the punch that the Boberg carries. I'm sure the Rorhbaugh will serve you very well and if I had one, I doubt I'd be dropping coin on a Boberg either. I'd be glad to let you shoot mine once I get it.