Do they no longer exist? I presently have an older ASUS VW266H and would like something at least that size or larger while maintaining a 16:10 aspect ratio - are there any options or does everything top out at 24" these days?
You can get a 4K monitor and use 1:1 pixel mapping to show 3456x2160 which is 16:10. That is admittedly a pretty strange resolution, which could cause trouble in games and apps that absolutely will not support custom resolutions, and UIs might get borked too.
Alternatively, a 39" 4K monitor at 112.97 ppi will show 2560x1600 at 26.72", which is close enough to being a 27" 16:10.
If it is possible to use 1:1 pixel mapping on a 50" 4K TV (and I do not know if that is possible) then you could have a 25.7" 1920x1200 display or a 34.26" 2560x1600 display.
50" 3840x2160 monitor = 88.12 pixels per inch (ppi)
1920x1200 at 88.12 ppi = 25.7"
2560x1600 at 88.12 ppi = 34.26"
If you go down that road, you can do even more square resolutions like 4:3 or 5:4, or even the literal square 2160x2160.
Edit: if you're wondering how I do those calculations, I just use this DPI/PPI Calculator to calculate the ppi of the 4K monitor size I'm interested in. Then I plug in the resolution I want, such as 1920x1200, and adjust the diagonal by hit and miss until the ppi is the same as it was at 4K. Someone should probably make a calculator that makes this process easier, and pass it on to some site like WSGF; I have no idea how to make such a calculator.