Its interesting that this thread resurfaced now, as just yesterday I posted a patch to p5p to change the hash function that we use from the "OneAtATime" function to the "SuperFastHash" by Paul Hsieh. Details of both can be found in an updated version of Bob Jenkins hash article from DrDobs. The SFH is signifigantly faster than OneAtATime on modern machines, with SFH running about 3 times as fast as OneAtATime.
Anyway, id be curious if you have any tools or scripts that can be used to do some analysis on how the two functions perform. I plan to instrument a version of perl so I can do chain length histograms and things like that, but anything you might think of would be appreciated.