One possible fix:
Look for StringHasher in google v8 code (http://code.google.com/p/v8/source/search?q=stringhasher&origq=stringhasher&btnG=Search+Trunk). Main loop looks like this:
raw_running_hash_ += c;                                                                       
raw_running_hash_ += (raw_running_hash_ << 10);                                               
raw_running_hash_ ^= (raw_running_hash_ >> 6);  

It seems not to have same collisions with many different hash seeds.