Is there a (sturdy) stand out there for ‘over the mixer/CDJ’ style that is portable?
Cant find anything except an old DJTT thread that didnt go anywhere, except for people asking for the same thing back in 2010! Haha.
I bet you could use a Magma style stand for just that.
You won’t be able to put that “over the mixer” though due to the sloped feet.
crane stand pro can hold a cdj fine and slide under most mixers (easier if they are in a flight case), or even another mixer and slide under another mixer 
Does anyone really do this, though? Do you really want to restrict access to your mixer (that gear that gets most use during a set) with a player???
Doesnt have to be over a mixer. Just something that will elevate the S4, when youre in a booth that has next to no space for a S4, let alone a VCI100!
The S4 is huge so you’d probably need two stands to keep it steady.