We are looking to replace our shower head in our Master.
Would really LOVE a shower head with a slide bar. Specifically, we want two shower heads. One fixed (not a rain-shower, though) and one that slides on the bar.
Do you want to be able to use both at the same time, or just one at a time?
I have Kohler Bancroft separate fixed and hand shower (plus a rain head) and can operate them together or singly, but it requires a separate diverter valve in addition to the temperature valve. Kohler also has a package with the diverter on the fixed shower arm, but with that you can only use one or the other. btw - we love the Kohler showers - looks and function!
How much work were you wanting to put in? Grohe has some pure retro-fit kits for almost no work (just replace existing shower head piping). It appears to be a rain head which you were not keen on, but I have showered in the Grohe kits and it's decent (handheld is better though).
Here is a link that might be useful: Grohe Retrofits
I don't understand why you would need a fixed AND a slider handheld. We have a Grohe slider with a handheld. The head is a Relexa and the bar is something else, but they are interchangeable with Grohe. You can slide that sucker way up with just a touch and easily tilt it up and down to any angle. Then it lifts right out very easily to spray those other parts that down falling water misses.
This is very, very different from the (cheaper) ones that are not adjustable when you put the hand held head in it's holder, when you have to tighten a screw to keep it in a fixed place.
I have arthritis in my hands and this one is very easy to operate...and it looks good too!
I hope you have access to a plumbing store that has some of these types on display. Play with them and see how you like the way they adjust...they are all a bit different and I know you will find one that is just right for you.
I'm looking at the Hudson Reed website, and they have some intriguing looking ones. I don't know anything about their quality though.