I think you misunderstand what I'm trying to find. Almost all regular shutter releases can do the two functions I asked about. What I'm trying to find is a wireless shutter release with the two functions that also doesn't preclude me from being able to mount a speedlight to the hotshoe.
My hähnel Giga T Pro II does half-press half press for AF, full press for release or continuous burst. It connects to the remote port, so while the receiver can be mounted in the hotshoe, it doesn't need to be (which is good, as that's where the ST-E3-RT sits.
When your ST-E3-RT is on the hotshoe, do you just have your hahnel receiver dangling from a wire off the 3-pin port or something?
If you're worried about vibrations caused by the very light receiver hanging from the port and swinging in the wind, you can velcro it to a tripod leg or mount:
Or if you get really anal, you can use the thread in the base of the receiver and mount it with a more solid option:
Such as clamping it onto a tripod leg:
Yeah, having all that stuff clamped and velcroed is one way to do it, but I think you might be missing what I'm getting at here. The reason I was asking about the RT system in my first post was because I was hoping it would help me NOT have to carry all that other stuff. In other words, no extra receiver module necessary for a remote shutter release, and therefore no cord either; a double-win. I was originally hoping that with two 600EX-RT modules, that I could "cut out the middleman" and not have to even buy or carry around a "wireless remote + receiver + cord" combo, and simply use one speedlight to trigger the other. Unfortunately, I learned in this thread that the speedlight's shutter release button does not have the two functions I outlined in my first post.
Ideally, I would have one 600EX-RT (or ST-E3-RT) on the hotshoe (with either the flash turned on or off), and have a cheap trigger that sends a RT radio signal to the hotshoe unit to fire my camera. If I could do that, I wouldn't need to buy or carry around all that other gear. No receiver bricks, no wires, no velcro, no L-bracket clamps,...nothing! Wouldn't that be great? I mean if Nikon can do it, how much of a stretch is it for Canon to have this clean solution as well?
I did look into the Yongnuo YN622C and the cheaper YN603s, but in the end they are also "middlemen". The former does ETTL and the latter does manual, but neither is ideal because neither leverage the RT receiver that's already built into the 600EX-RT.