I wouldn't use Ocaml (and, to a similar extent Haskell or Erlang), for anything beyond research projects or small prototypes. These languages are research-driven, not community driven, and they have plenty of features that nobody wants except the maintainers. In the case of Ocaml, just take a look at crap like camlp5 and polymorphic variants.
Language shootouts are poor benchmarks for the quality of a languge. Better metrics are community activity and the quality of the libraries.
You are completely wrong about Erlang, which is absolutely not a research language, but when combined with OTP a very pragmatic tool designed by Erlang to answer their specific needs. Now it doesn't mean that it's the right tool for any problem, but when used for the right jobs, it is awesome : elegant, mature, rock stable and definitely production ready. And the community is growing...
For more generic purpose as far as functional languages are concerned F# might have a go, if Microsoft continues to push its efforts to integrate it in Visual Studio and make it mainstream. With .net/mono under the hood the libraries are there. Not completely production ready yet in my opinion, but hopefully soon I'll be able to use it instead of C# when I have something (fast) to do on top of mono...
The AXD301 ATM switch, one of Ericsson's flagship products, 1.7 million of Erlang code. This is just one example of large-scale software projects written in Erlang. Your perception of it as a research language needs to be re-evaluated.
I just wanted to clarify the other comment to this, erlang was was written at erickson to solve specific problems, it was driven by a business need, not communities or research.
Language shootouts are poor benchmarks for the quality of a languge. Better metrics are community activity and the quality of the libraries.