The question of hashes came up on the perl5-porters mailing list earlier this month. No definite decision to change the internal hash function was reached, but a number of hash implementations are compared and benchmarked. You might want to see how this Google hash fares. (Assuming we are talking about the issue).

Update: it would be better if I posted the links: See http://dev.perl.org/perl5/list-summaries/2006/20060501.html and http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2006-05/msg00261.html