They still make them, but most big box stores don't carry the separate handles, or have a very limited selection. Try an online or large plumbing supply store. I have a similar problem and did find quite a few by various manufacturers--may have to replace the whole assembly though. Most places I've searched online had Q&A so you can make sure you get the right thing, and you can download the spec sheets and drawings to make sure. If you get a pressure-balancing or thermostatic valve (basically the same thing to keep the water from scalding you) make sure it is for two handles. An alternative might be to patinate the old fixtures (they could go dark) Here is a link with various ways to do it: http://www.ehow.com/how_13285_oxidize-brass.html If you are getting rid of them anyway, may be worth a try, especially with the less toxic chemicals method. Probably best to do in the garage or someplace, rahter than in place, to avoid messing up the tub or tile.

Hi Norm, it would be a volume control valve, as I want to control the flow to a handshower and the flow to a shower head fully independent. I found a Hansgrohe volume control valve in the meantime that seems to fit the Grohe Concetto, it is the Axor Uno. I also looked at the Kohlers, the alternative is the Kohler Stillness, which looks very nice and modern, but I am concerned that the different handle style to the Grohe Concetto could be an issue. The Hansgrohe has a simple round shape and therefore appears to be less of a style conflict. Thanks for your recommendation to look at Kohler!

Go to Houzz Products. Click. Scroll down to Windows and Doors. Click. Scroll down to Interior Doors. Click. Find the search box that says Style. Click. Scroll down to Contemporary. Click. There are about 800 photos in this category. You may save your favorite photos in your own Ideabook. Even if you are not sure about a photo, add it right then. It is impossible to find a specific photo in Houzz unless you have the photo number. It is easy to delete a photo from an Ideabook.

The mixing valve body was installed too far forward. As your plumber said the only repair is to open the wall and move it. Maybe you can share the cost?