To be honest, I have no idea how to implement the exact operational semantics of prototypal inheritance in a dynamic language with classes. (Perhaps it is possible, but I would not bet on it.) In JavaScript, objects are statically known to be internally a pair of a base reference and a hashmap. In Python, you can define a tuple or class that has a base reference and a hashmap as members, but internally your program will test for the existence of these members all the time. So, different semantics.
But a static OO language can faithfully reproduce the operational semantics of prototypal inheritance.
The difference between "checking for the existence of the proto key in a hash map" and "checking whether the proto pointer that I am certain to have points to NULL" is due entirely to the differences in the semantics of Python and C++. Is it important just to implement prototypes, or to ensure that the guts of the prototype system are the same as the guts of a particular JS implementation? I'm not sure precisely where the goalposts have gone, so here are some prototypes in Python. http://pastie.org/8263966
Edit: Now with method binding that works instead of not working!
But a static OO language can faithfully reproduce the operational semantics of prototypal inheritance.