Probably the best book on the subject is <a href = "http://www.roadtripamerica.com/read/Watch-It-Made-in-the-USA.htm" >Watch it Made in the USA</a>. A couple that I know of would be:

Cerreta' Candy in Glendale; The Ping Golf Club plant and the Peanut Patch in nearby Yuma.

You might also look at some of the <a href = "http://www.roadtripamerica.com/links/destinations.htm">Destination listings</a> we maintain (factory tours are not the focus, but there are wealth of ideas nonetheless).