Here's a patch for 3.3, which consists mostly of tests. A couple of points:

  o I removed the len > view->len check in PyBuffer_ToContiguous(), since
    the function is not documented and silently accepting output buffers
    that are too large seems unusual to me.

  o Removed the comment in bytesobject.c "Better way to get to internal buffer?".
    IMO the answer is no: There isn't any better way that works in full generality.

  o Removed the "need to check for overflow" comment: ndim is now officially
    limited to 64.


I think this can go into 3.3: It's easy to see that for contiguous buffers
PyBuffer_ToContiguous() behaves in the same manner as before (except for
the len issue).

For memoryview, buffer_to_contiguous(x, y 'C') is literally the same
code as buffer_to_c_contiguous().