Edit: should have mentioned this earlier for an example - xmonad is written in haskell
And of course Minsky's employer, Jane Street Capital, writes everything in OCaml.
There are plenty of commercial users outside the financial sector too but those users tend to be smaller companies.
You are right, OCaml doesn't see too much use outside of Jane Street, Citrix and a few others. I think the academics mostly left it in favour of Haskell. Also the owner of the OCaml project didn't embrace community development early on. It's more like a cathedral than a bazaar. They are signs showing to change, but it's probably already too late for mainstream popularity.
I'm not sure about the performance issue. If it stays within a reasonable (low single-digit) factor I think the hit is worth the quality guarantees you can get out of it. The hiring/education issue is probably the #1 reason so few attempts are made in this direction.
http://www.haskell.org/haskellwiki/Haskell_in_industry has experience reports for Haskell.
Galois and Standard Chartered both have large Haskell teams, for example (I've worked for both).