OCaml is non-Unicode by default, though there is Unicode support in extlib (http://code.google.com/p/ocaml-extlib/).

I, too, am curious about a Haskell implementation - I suspect it would be comparably efficient to the OCaml one. As for optimizing the Ruby one, the major speedups come from being able to parallelize processing (not sure how feasible this is in Ruby) and OCaml's static typing system (Ruby loses big here, speedwise).

I also wonder how fast it would run in Lua; probably somewhat faster than Python. I don't have the time to rewrite it ATM, though.