David Hackett posts an article on Elemental Ray Blog, taking a look at creating an using Object Lights in Mental Ray 3.11, using the new builtin_object_light shader included and shows how to show the shader in mental ray for Maya.
The usual reasoning is that object lights can generate a lot of noise in a render that is difficult to clean up. However, since the inclusion of Unified Sampling, you’ll see that cleaning up area light noise is much easier with fewer samples than before
Knowing that mental ray for Maya has poor integration, you would expect no less than a trick to expose the builtin_object_light shader in mental ray 3.11, and David shows how to declare the object light shader.
There is also bit about the workflow for using the builtin_object_light shader, and how to clean up noise using the new Unified Sampling in Mental ray. Check out the post for using the Built In Object Light Shader in Mental Ray Maya here.