Re: LCD (large -- TV-ish) monitors with SOLID front surface?

It sounds like you want to put a glass screen protector on the front of a regular monitor (the front of a regular LCD monitor is the plastic polariser)

The largest glass screen protector I've seen was for a 10" tablet, but they may make them in larger sizes.

it is a thin glass sheet some fraction of a millimeter thick and about as flexible as a payment card. there is a weak pressure sensitive adhesive on the back side. (some sort of "peel and stick")

Similar protectors are used on mobile phones.

It's supported by the ahesive and the display it's stuck to. if you only want to protect the display from chemicals and abrasion then thin will work.

If it was stiffer than the display glass you'd need to disassemble the display to install the protector. (if wanting to mount it using adhesive)

Or else live with a gap between the display and the protector (increasing parallax and potentially collecting debris)

Have you switched fron non-visible ink to virtual ink? Do you actually want a touch sensing screen?

These days they use actual displays instead of chromakey. Sometimes even touch sensing displays; there's funny videos of the presenters discovering this: eg.

Not knowing your actual requirements I'm going to refrain from making specific suggestions.