Madebysofa Does It with Python and Cocoa in the ADC article:
Using Python and the PyObjC bridge gives you the best of all worlds—Python and Cocoa. Python is great for unit testing and agile development. Because Checkout manages critical business information, we swear by writing unit tests for everything that even comes close to any financial data. And since Python is interpreted and not compiled, launching a debug session takes seconds. You can make a modification and see the effect of the change immediately.
They are European. They also mention localization as an advantage of Mac OS X software development. The company name, Madebysofa, might not be well-recognized, but they are the guys who made a much controversial app, Disco. The UI and icons are made by Jasper Hauser of Camino and Adium fame. They are the “Delicious Generation”.