You can do it now with 1.42 and onwards.
In the System menu check the box that says “WIndowed”
That will give you the ability to put the faders on one screen and the touchscreen view on the other screen.
I do it with my DELL XPS all in one touch with an external ACER monitor plugged in.
FYI you can also do this with iPad/Macbook Combo (although of course MacBook isnt touch)
Download the APP DUO and you can do split screen with an iPad plugged into a Macbook (but could also work with Mac Mini and two touchscreens)