I talked to a MacRhino user today on support.
He did not see the File -> Page Setup in the latest build 3-17-14.
So, I updated to the 3-17-14 build of MacRhino.
I can confirm that I also do not see this File -> Page Setup under the File menu.
I had the 3-5-14 DMG in my download folder, so I re-installed it.
Now I have File -> Page Setup.
You may wan too skip this update if you need this command.
I am sure Marlin with advise us.
McNeel Technical Support