Anything that has a removable eyepiece seems to be a prime candidate for this technology/adaptation of old technology.
I'm still betting Vortex, but hoping Kowa. Maybe Meopta...
I can't imagine that the scopes with fixed eyepieces would be good candidates for this which rules out the TS line from Swaro, Maven S1, but this is all just amateur speculation from an uneducated/ignorant user.
Wouldn't the TS scope/line already undercut sales of the TX line? Perhaps they are trying to "force" people up to the TX level with the binoviewer.
Highlander from Kowa seems to be a VERY niche product where the spotting scope market is already pretty big by comparison. How many Roksliders would consider the Highlander vs. how many would consider a binoviewer for a spotter... I'm willing to bet that Kowa wouldn't leave that $$$ on the table.
The bino viewers are really not too expensive that I've seen (obviously they're meant for telescopes). I don't think this is cutting edge stuff and I'd be surprised if there aren't "followers" pretty soon.