Do a hardware render of the scene in Maya, in wireframe mode.Keep the multi-pass options checked to 3.this way you'll get a smooth wireframe render.
Take the image into photoshop alongside your final rendered colour image.
Open the wireframe render and paste it onto another layer in photoshop above your colour render.
Now you can erase the parts that you dont want so that it looks 50/50.
tip : Try using the different layer modes in photoshop like screen, multiply, add. overlay etc.