The 21 round is actually 19" viewable so I would still see the CBS as serious competition for RCA. Maybe CBS couldn't tolerate losing money the way RCA was determined to (RCA having deeper pockets and also eyeing potential broadcast sales if TV buyers demanded more color programing)

ETF just listed one (with photos and more) in their "what's new" section.

Did CBS-Hytron continue to make color CRTs after the 19VP22?

It's hard to believe they had prototype tubes with phosphor stripes & grilles (like modern ones) in the 50's. Solving color display was a tantalizing quest for 1950's inventors. It would be good to find a Lawrence (sample 22" Chromatron) tube or Philco 'Apple' tube/TV today, or one of those limited production Sony chromatrons (it would have to be displayed in a glass case protected by laser beams)

About EVERY company/establishment I know of, that has been established for quite awhile, has at least ONE "Gooleyhole".. a place where experiments that didn't quite make it go, the boss' sailboat, pet projects, or stuff they're still carrying on the books but will NEVER be looked at again, go to languish...You gotta wonder what is hidden away in dank, dusty corners of electronics companies...

I bought a Sony single tube projector on eBay that had an Indextron tube in it. It worked for about 10 min after taking out of the box. I started troubleshooting it without a schematic, scratching my head saying to myself what the hell? What’s all this digital stuff doing in the video circuit? Why is there only one video feed to the CRT socket board? I had no idea an Indextron existed. So I got out the ESR meter and changed the bad caps and it worked. It was not until after I sold the damn thing that I figured out what it was and how it worked.