cbuffers

cbuffer WindowBuffer // Rarely, if ever, updates
{
    // ViewProjectionMatrix will go here
};

cbuffer NodeBuffer // Buffer from attached scene node; shared with other instances
{
    //NodeMatrix will go here
};

cbuffer InstanceBuffer // Buffer from instance; one per instance (might make into vertex buffer)
{
    // InstanceMatrix will go here
};

cbuffer SomethingSomething
{
    // Something will go here
};