Why was the mpz module removed from Python 2.4 in the first place? 2.3
has  it.

I see three way to implement the option:

 * Let somebody implement a mpz type as a 3rd party extension.
 * Let somebody implement a mpt type and ship it with the Python core
 * Let somebody write a patch that replaces the built-in long type
implementation with a GMP based implementation (./configure
--with-gmp-integer)