Issues:

1. In Py3.0, the cmp argument has been dropped completely.  It has been 
supplanted by the key function.

2. Previous feature requests for cmp/key/reverse have been rejected. 
The problem is that in a series of searches or insertions the key 
function should not be called more than once (as it is with sort), but 
the bisect functions potentially call it many times will the same 
argument.  The granularity is wrong.  Adding the cmp/key/reverse 
arguments tends to discourage correct design with a separate key table 
and a set of indexes.

3. Guido has articulated as design principle that prefer separate 
functions to having a flag, so the separate handedness functions should 
not be combined.  Also, the current design reflects typical use cases 
where an app decides on a handedness and never changes that decision.  
It would be a waste to repeated pass in a handedness argument that 
never changes.

Marking this as rejected so that you don't lose more time writing C 
versions and whatnot.