It looks like the new OS X version will allow a mix and match with Python and Objective-C. There's now a full bridge connection Python and the Cocoa libraries: To open up the benefits of the Cocoa frameworks to a wider developer audience, Leopard embraces two other highly dynamic languages for use in building Cocoa applications: Ruby and Python. These two languages are an excellent fit for integrating with the Cocoa frameworks, and they both have high quality bridges to Objective-C. These bridges allow you to mix and match Objective-C, Ruby, and Python, allowing you to choose the best tool for the job at hand while using high level Cocoa features such as Key-Value Coding (KVC) and Key-Value Observing (KVO). so the developer can access the whole OS X gui framework from Python code. Check out the description here