were there ever prototypes of > 25v crt's?

[freakaftr8]

Hey all and Happy New Year you everyone!!

I was thinking last night as I watched the ball drop on both my Sony 36XBR450 and one of my ctc 17's. Of course as I watched yeas the picture on the sony is far bigger. Did they ever make a prototype or something along thaose lines for a color CRT of the 60's or early 70's to take place of a 25v style 23" CRT? I can imagine if so it would have needed a hefty FBT huh!