We could add a flag memoryview(x, raw=True) to the constructor.  This view 
would behave exactly like the regular one except that it ignores buf.format 
entirely.

So you could do assignments like:

   m[10] = b'\x00\x00\x00\x01'


This would be more flexible in general since memoryview currently only supports
native struct formats (complex formats slow down certain operations dramatically).

I think the feature would not add much additional complexity to the code.


The question is:  Is this a general need?  Are many people are using memoryviews
for bit-twiddling?