This sounds really interesting and compelling. As someone new to Go... What would be the advantages of using Go over Python (taking into account the emergence and future ascendancy of pypy)?
Concurrency is a hugh difference. Python's approach to concurrency is the "global interpreter lock" which means only one thread can be running at once to prevent you from trying to access shared objects from multiple threads. Go has lite weight "go routines" that are multiplexed across os threads in parallel and channels that can be used for passing variables between them and the defer statement to help clean up. This sounds complicated at first but it is the simplest system for reasoning about concurrent code I have used.
Go also has pointers, mutexes, fixed sized arrays (with easy to use dynamic slices over them) and other things that let you implement low level data structures when you need to.
Go has interfaces and embedding but no inheritance which leads to iterative development of organization instead of needing to design from the start. The standard library makes extensive use of these and is extremely well organized...I much prefer go's http client code for example.
It doesn't have as extensive a corpus of library implemented in optimized C/fortran and I really miss things like numpy...in many cases python code can be faster because the libraries do all the heavy lifting.