Yes, it's an excellent idea, but is it feasible?

I think it is and it could even be easy. Just check the material names when the UI list is created and skip those with the mentioned prefix.

It all depends on how the list is used after it is created. A 'missing' material name might interfere with the correct execution of other functions in the Modify furniture dialog. Once that dialog is closed everything should be the same as before and the hidden/invisible part is untouched.