I've been using OCaml to build a language and runtime system for cloud orchestration[0]. As part of that, I've developed an AWS library whose code is generated from the service descriptions published by boto. It will be open-sourced at some point in the future, along with a few other things that should make developing web stacks using OCaml much easier.
If you're looking to try out OCaml, I'd say the time to do so is quickly approaching.