About the light panel color, maybe you could apply a [font=courier new]light_mat[/font] material on the mesh (see the end of [font=courier new]exportAppearance[/font] method)?

My first tests were inconclusive because all the objects in the scene had the 'light_mat' material.
By applying it only to opaque light sources, I get this result.

You will notice that unlike SunFlow, the YafaRay rendering engine does not take into account the light power for the "glow" effect.

I just released the final version 1.0 of the YafaRay rendering plug-in.

For a first version, this plug-in keeps its promises!
In order to finalize the integration of YafaRay with the PhotoVideoRendering plug-in, I still have to bind this rendering engine to the photo panel at points of views and the video panel.