This thread is old but maybe this comment will help someone else who has decided they want a hand held. Don't listen to the naysayers. You don't need to buy a new valve with a diverter and a cover plate. The valve that you have has 4 ports. One for hot water, one for cold and a third one goes to the shower head. The fourth, down to the tub spout would normally be capped if you don't want a tub spout. (You can go in through a wall behind the shower so that you don't destroy the tile.) Instead of capping it, sweat solder a short piece of tubing that extends off to the side. Onto this tubing, solder a brass elbow with female pipe threads (just like in the wall at the shower head). Screw into this elbow a short brass nipple that will extend through the shower wall to a nice chrome attachment mounted on the wall to which you can connect the shower hose. You'll need a diamond hole saw to cut through the tile cleanly. (Then mount the hand held anywhere you want, like in the picture.) Easy peasy. Any plumber would understand these instructions. The water will normally come out the hand held (just like with a tub spout), but by pausing the hand held, water will come out the shower head. The hose is is only under pressure when the pause function is engaged and the water is running. You'll be in the shower if it breaks.--no risk of water running during your 2 week vacation. If the hose has to be replaced in 3 or 4 years, so what? The pause function on the hand held means that the hose was designed for intermittent city water pressure. It's a Delta. The hose will be of good quality. ...Now just repair the drywall in the adjoining room.

"The 1st picture on the left has the hot and cold supply lines attached to it? The picture in the middle does not work with the 1st picture?" Correct. The middle picture in your first set of pictures and the last two pictures use a Hansgrohe iBox rough valve. The cartridge, which comes with the trim, determines if it will be pressure balanced or thermostatic. The iBox is what I use. I am not familiar with the showerpipe as I don't like it so have never looked into it. The S/E trim you show does not have a diverter. It would be for a shower only or a tub only. You turn the handle and how far you turn it determines the temperature. The flow stays constant, just the temperature changes. The Metris C trim you show has a diverter so it can have 2 functions. Tub and shower, 2 different types of shower, etc. You turn the top handle to determine where you want the water to come out. You turn the bottom handle to determine the temperature. The flow stays constant, just the temperature changes. The escutcheon is the big round piece that covers the hole. It is part of the trim package. The trim package includes the cartridge, escutcheon, and handles. The cartridge determines if it is pressure balance or thermostatic, and if it diverts or not. The iBox valve itself is the same for any configuration (but it might not use all of the ports, in which case your plumber will cap one off). I don't know what you mean by an integrated volume control, unless you are referring to a thermostatic valve. With a thermostatic valve, you can control the volume of water independent of the temperature. Pressure balance means water is either on or off, no volume control other than that. Thermostatic means any amount of water flow you would like. With thermostatic, you can leave the temperature setting alone so it will always be the temperature you like without having to adjust it (assuming no one else adjusts it). Once again, the shower head and slide bar DO NOT have to be the same brand as the valve. They are independent pieces. You can change them at any time if you don't like what you originally get. It doesn't matter what brand valve you get, you can use any brand of shower head. I actually do not like the hansgrohe wall outlet (used with a hose and slide bar or hook). It looks and feels cheap. Rohl makes a nice one, with an adjustable escutcheon. Delta is a similar setup to the Hansgrohe iBox; it's just not as flexible with installation.

Dornbract has some models with only two valves needed for two showerheads: one valve for thermostat and second valve is a combination diverter / volume control. Turn knob to the left to control volume for one showerhead and to the right for the other showerhead. Otherwise, most shower systems that I have seen require 3 control valves: thermostat, diverter, and volume. I am in CA where only one showerhead can be in use at a time. Make sure that the valves are placed on interior walls and are easily accessible from both inside and outside of the shower. The valves need not be on the same wall as the showerheads.

HU- I don't want to "permanently fix the temperature." Only one of the three showers in my house is currently working. Not everyone in my household likes the shower water at the same temperature. The diverter integrated with volume control will work only with two outlets. If I wanted three outlets (e.g.. jet shower head, handheld, and rain head), I would need to have the diverter separated from volume control, as in my primary shower (see photo below). I think Axor, Hansgrohe, and Dornbracht may be the only suppliers available to me that offer a two-way diverter integrated with volume control. With this configuration, I need only two levers -- one for thermostatic control and one for diverter / volume control. Actually, the wannabe-plumber (GC's friend / "employee") messed up in my primary shower when installing the rough-ins -- I will need to rip out tile and redo to get hot water. It was my designer's idea to swap the tub and shower from their original positions, which landed the shower valves and heads on exterior walls (the shower area is a "bump out."). The architect had proposed a neoangle shower in the primary bathroom -- but that was nixed by the GC and designer.