If you want it to be fully native and not have to carry a runtime, C++ is pretty much your best choice. I think technically Python could be pretty slim if you j

If you want it to be fully native and not have to carry a runtime, C++ is pretty much your best choice. I think technically Python could be pretty slim if you just bring the runtime and build the GUI out of raw Win32 calls in Cython. That is something I've been thinking of trying for a while but mostly as a toy project to see how small you could get a Python GUI tool and not something for production.