Scarlet looks to be a wonderful camera and will fill the needs (and wants) of nearly all of us. However, we have no true idea of when the camera will be released. For those who followed the Red One's release, the company was more than a year late releasing the camera since they made so many changes to it, and one they were finally released, it was basically a Beta camera for the first 6+ months. Worth the wait for sure, but its a big unknown.
With regards to Scarlet, the company has already completely scratched their first concept released last summer when they announced a completely redesigned versions of Scarlet which is now in development. Red was saying Spring 2009, but now they do not even have a time listed.
Housings are a whole different issue. The design Gates has done for their Red One housing, called the Deep Red, has the most intuitive engineering and designs I have ever seen on an underwater housing. HOwever all of that hard work and design has taken at least a year before the housing is released (slated for March release). With the lack of actual specs and prototypes, as well as unknown time of release, the housing manufacturers seem to be unknown as to whether or not they will house the camera.
Personally, Id love to see a Scarlet housing from Gates or any of the housing manufacturers, but I think it is going to be quite some time before any of them commit to designing one.