I don't think RubyMotion exists because like Obj-C it was inspired by SmallTalk. Well maybe it is, but that doesn't mean it's an insurmountable barrier that would render a similar project in python impossible or "un-python like". C#/.NET got the treatment a long time ago, http://xamarin.com/. It's just that (it appears) no company or OS developer has taken on the challenge of creating the tooling for python.