Dual Lightmapping is the Unity method for this. http://unity3d.com/support/documentation/Manual/LightmappingInDepth.html I have Unity Pro here, but haven't tried it on iOS.
Starting to put everything together in Unity and playing with the lighting/mood. Still working on the shaders in Unity, especially for the "Screens/lights" and the robot bust hologram.
Just a friendly bump, the Unity 5 metalness preset doesn't seem to be outputting what Unity is looking for in the metallic map: Metallic (R) and Smoothness (A).