Yep, 1/2" copper won't deliver over 4 gallons a minute which is what you'll be using if running both features at the same time. Even if you choose features that use less than 4 gal/min you'll be so close as to not want to chance it.

So the source of the hot water is my water heater, I'd run a 3/4" line out of that to the shower area for the hot then to run a 3/4" line from the house's main water shutoff valve to the shower for the cold water?

bump

i'm going to watch this one... almost exactly what I want for my mstr shower next yr... I also want a regular shower head tho.
a separate control for shower head is fine...

Unless some manufacturer has a volume control that can do either the jets or the handheld or both, you'll need one volume control for the handheld and one volume control for the body jets. Assuming that you want the water at the same temperature coming from both the handheld and the body jets, you'll need one thermostatic valve.
It may be possible to combine the controls into one valve, See the Hansgrohe manual, below.

Here is a link that might be useful: Hansgrohe

Well...first you need to find out the worst case scenario. Add up the flow for your two body sprays, plus the flow of your shower head.

That's the GPM that you need to carry to through your shower valve and to your diverter. You;ll need a valve that can pass through that volume of water.

You can do what you want with an A/B/AB diverter.

Coming out of the diverter is where you can run one 1/2" copper run to the shower head and a second 1/2" copper run to the body sprays.

That's when using a separate on/off valve and a separate diverter.

However, for your setup, you can run all three outlets from a 1/2" copper supply going into the valve and with 1/2" copper running from the valve to the fixtures.

There are quite a few valves that can do what you want. One of the last houses I did I used Hansgrohe Thermobalance III valves in all of the bathrooms in the house. The TB III is an A/B/C/BC type of valve. It's also a 1/2" valve. I used it that way in a couple of the bathroms, in others the A and B outlets are looped together (let's call this new combined AB loop "D") so you now have a D/C/DC setup.

"D" can be your shower head.
"C" can be your body jets.
"CD" can be your car wash with everything throwing water at you.

In case that's confusing, think of it as the A/B/AB valve that I described in the beginning.

It's an approved way to plumb the valve, and it with the TB III having ON/OFF, temp, and diverter all in one valve, you'll have an uncluttered wall.

But again, besides the TB III there are other valves out there.

So can you do it with a single control head? Yes.

Can you do it with 1/2" copper into the valve and 1/2" copper coming out of the valve? Yes.

Great info, thanks! I see there is a Hansgrohe Thermobalance III trim in Oil Rubbed Bronze that will work. Does anyone know of any other manufacturers that make a mixer/diverter all in one like the Hansgrohe Thermobalance III? I've checked websites of the usual suspects (Grohe, Moen, Delta, Price Pfister, etc.) but haven't come up with anything else, am curious if more options beyond this one.

Don't forget that you'll have to up your drain size to deal with all of the outflow from such a setup. And, is your water heater of a large enough size for this? Using all of the sprays, a typical 50 gallon water heater will give you about a 7 minute shower before it starts to go cold. You may want to upgrade your water heater while you're at it.

thx! i'm gonna save this...

my water heater is 11 yrs old now so I'm planning to get a new one anyway. and it's just me here using hot water (any water!) so if I run out I won't mind after having 7 mins of bliss on my aching back... it'll be so worth it to me!