In the UK:
http://www.organworks.co.uk/
I believe this company built a Hauptwerk organ for the BBC, but I have no direct experience of their work.
I'm hoping there will be further replies, as I'm thinking about a keyboard with second touch built in for theatre organ playing. When I last enquired this was quite expensive - around £1,000 - but I think I read a post somewhere on this forum from an English company that might not be quite so expensive.