Python has a lot of GUI libraries: tkinter, wxWidgets, pyGTK etc. But all these GUIs need to be installed and quite heavyweight, so it's a bit complex to deploy end-user GUI python apps that relay on mentioned GUI libraries.
Recently, I have thought about python's built-in ctypes module. Theoretically, it's possible to create a pure python GUI library that will use ctypes on windows ( windll.user32.CreateWindowEx, etc ), native pyObjC on MacOS and pyGTK / pyQt on gnome / kde. Does such a library exist? If not, what do you think is wrong with this idea?
Tkinter is part of the python standard distribution and is installed by default.  Expect to find this on all python installs where there is a graphical display in the first place.
Pure python gui library?