No, the sentence is not okay. "Much more" is not used that way.
As you say, a better phrase would be "not to mention..." or "as well as..." or "plus, of course,..." or (less strongly) "in addition to...."
In addition, the "not to be mentioned" thing takes the definite article:
The guests were served caviar, truffles and foie gras, as well as the usual steak.