These instructions have been supplanted by an automated, scripted installer, which lives here:
https://github.com/mikepurvis/ros-install-osx
Please try it out, and file bugs as required. Feel free to browse past versions of this gist as a historical curiosity, but I won't be monitoring or supporting it any more.
Doing rosinstall_generator rviz --rosdistro hydro --tar >> indigo.rosinstall doesn't work in my case. I still have the "could not serialize mesh" error.
My solution has been to manually fetch rviz from github and change the branch to hydro. Also, since rosinstall_generator desktop already pulls in rviz, doesn't the second line create a conflict?