Embarcadero has rad studio XE4 which can create windows and OSx binaries if you use c++. If you use Pascal, it can do iOS and I think Linux as well.
It requires both a PC and a Mac to do this. It works by utilizing OpenGL calls to render the GUI, so the hardware you are using must support OpenGL (or D3D) for it to work.
If the app were written in C++, I might be able to help .... assuming that some free time ends up coming my way sometime this decade