Hmm I doubt it, since the lookups are done inside of the global distance field which is a composite of all the DFs. Doing channels would essentially require multiple global distance fields to be constructed and the global lookup is already a fairly high overhead system since it has to build it 3 times at cascading resolution for the clip maps. That is why when you add “Get distance to nearest surface” to a material you will see a pretty huge increase in shader instructions. Supposedly the rendering cost isn’t quite as high as the instructions since the branching means the gpu chooses between the 3 clip maps rather than doing all of them, but it sees all of the instructions none the less.
Of course maybe there is some way to add that as a new feature that looks up individual distance fields rather than the globals but that would also be much more expensive.