Looking at interactions with (and by extension, programming on) FPGAs, where everything is bit-based, it's common to find things like 14-bit values. We have 14-bit types in our internal type system.
Yes, but "a 14-bit type exists" is not the same thing as "CHAR_BIT==14". I would be as surprised as Lyberta (and perhaps more so) if any C++ compiler in the world supported "CHAR_BIT==14".
However, I agree with Tom that this proposal is not motivated. Personally I think it'd be just as silly to have CHAR_BIT==16 or CHAR_BIT==32 as to have CHAR_BIT==9 or CHAR_BIT==24. If we're trying to get C++ to fall in line with what "everybody knows," then the way to do that is to mandate CHAR_BIT==8, not to keep the current situation of "CHAR_BIT==I don't know, ask your vendor" but also put odd restrictions on the vendor's choice.
Lyberta, did your survey turn up any C++ implementations where CHAR_BIT != 8? If so, what version of C++ were they — C++03, 11, 14, 17?
my $.02,
–Arthur