Is there a source for a neutral gray paint designed to be used on floors and/or walls in a TV broadcast studio?
I am not aware of a specific standard or source for gray paint for TV studios. If you take a sample of the desired gray to a reputable paint store, they can measure it and produce a very close match. In your situation, and 18% photographic gray card might be a good choice to match. That is a bit darker than typical viewing booths, but I would think a slightly darker surround would be good in a TV studio.