Fatar make them.
http://www.studiologic.net/ I'm sure you can get them cheaper than the prices listed there - That page makes them look more expensive than getting a stage piano, albeit you get all the midi bells and whistles I suppose.
They seem to have a questionable reliability from postings / reviews I've seen. That said, some of the digital piano manufs use fatar actions, I don't know if they are identical, if so maybe the reliability issues were for the earlier models?