Well I can think of 3 operating systems written in Haskell now. One was an executable specification for validating a secure L4 implementation. One is hOp, and then there's also House, based on hOp.
Keep in mind that House and hOp both used the ghc runtime (written in C) as a base. I would argue that this is most of the "OS". The seL4 spec is more like an operating system simulation than an operating system (or more accurately it is a spec that can be executed).
I'm not familiar with the other projects you mention. Thank you, I'll check em out...
I've been writing a good bit of Haskell these days at work as well, mainly due to the fact that it's possible to write some fairly sophisticated code quickly, and even get pretty darned good performance out of it.
I'm a big fan. Just want to make sure the hype isn't overblown. Tim Newsham http://www.thenewsh.com/~newsham/
