A suggestion, if possible, is to add an option to VrayDecal to apply it to a specific material. For example, in the case of objects with multi-material, apply it only to the specified ID or material name.
Purchase the rights for old Mental Ray plugins so the scene converter can import them
Is there any way Chaos could buy up the rights to make scene converter work with old Mental Ray scenes? I would love to be able to open up some old projects and freshen them up.