Keep in mind that Free Pascal is not exactly the same as classic Pascal. The language has a lot of features you'd find in other modern (as much as Java and C# can be called modern nowadays anyway) object oriented languages. Things like classes, interfaces, dynamic message dispatch, properties with getters/setters, for with ranges, dynamic arrays, generics, a rich RTTI (though not as rich as managed languages - yet, it is work in progress - it is rich enough to do things like serialization, etc), etc.
As for a C++ version, it would be useful (though i find Free Pascal a better language overall, despite its warts - the only thing i wish it had from C++ was 'const' and slightly more powerful generics, but both aren't that big of an issue and generics are improving anyway) but VERY difficult to do as i wrote some time ago here [0] and here [1] where i went into more details about the language side of things (C++ Builder has extended C++ to allow for Object Pascal-isms because VCL itself is written, like LCL/FCL, in Pascal, which for Borland was possible because they made both the Pascal and the C++ compilers).
[1] https://news.ycombinator.com/item?id=19882489 (note that the discussion was originally about using LCL from C++ so i also mention the alternatives - and how not having the rest of the IDE would end up with a worse wxWidgets since LCL isn't really designed to be used purely via code)
As for a C++ version, it would be useful (though i find Free Pascal a better language overall, despite its warts - the only thing i wish it had from C++ was 'const' and slightly more powerful generics, but both aren't that big of an issue and generics are improving anyway) but VERY difficult to do as i wrote some time ago here [0] and here [1] where i went into more details about the language side of things (C++ Builder has extended C++ to allow for Object Pascal-isms because VCL itself is written, like LCL/FCL, in Pascal, which for Borland was possible because they made both the Pascal and the C++ compilers).
[0] https://news.ycombinator.com/item?id=15893362
[1] https://news.ycombinator.com/item?id=19882489 (note that the discussion was originally about using LCL from C++ so i also mention the alternatives - and how not having the rest of the IDE would end up with a worse wxWidgets since LCL isn't really designed to be used purely via code)