Here's an experimental patch, against the py3k branch, that makes Python 
represent its long integers internally in base 2**30 instead of base 
2**15, on platforms that have 32-bit and 64-bit integers available.

On platforms for which autoconf is unable to find both 32-bit and 64-bit 
integers, the representation falls back to the usual one.


See also issue 1814 (GMP for longs), and the discussion at

http://mail.python.org/pipermail/python-dev/2008-November/083315.html

(note particularly Tim Peter's message at:

http://mail.python.org/pipermail/python-dev/2008-November/083355.html
)