I just started working at KULeuven, home of OROCOS but a different department. Everyone I have met here who is doing hard real-time is using Ubuntu with a xenomai kernel, ROS just as a package manager/build system, and writing all of their code as OROCOS components and running them in the orocos deployer.
I haven't met anyone doing inter-op between Orocos and ROS yet; I read that you can send signals between the two environments with some work, but their workflows and toolsets are mostly orthogonal. (i.e. Try using rosnode to list what orocos components you have instantiated or listing running ros nodes in the orocos deployer)