The 1951 Fox, Technicolor, feature "My Blue Heaven" also has many scenes that take place in a TV studio. While wide shots of a fictional variety show in production show RCA B&W cameras, all the TV studio monitor images are in color. This extends to shots of home receivers, and even a TV store with many sets on display show all of them displaying color images. These images were special effect insert color mattes.
I viewed the film on The Fox Movie Channel. Available on DVD.
http://www.amazon.com/gp/product/ima...6881510&sr=8-3
-Steve D.