Yes, you can do this with one TC and one AX. My current setup has changed since I wrote this article. My TC failed -- I think the power supply blew out during Sandy -- and the Airport Extreme died as well. My current setup is two Airport Express configured as described in the article.

You don't need an Extreme. That's just what I had in my setup. You can do this with any combination of Airport devices. You could do this with two or more AirPort Express (AX) or two or more Airport Extremes (AE) or two or more Time Capsules (TC) or One TC and one more AE/AX etc.