I am in Singapore and have just asked the same questions.
Nauticam is currently the only housing supporting the 11-24, housing + domeport roughly 6000 USD net.
Ikelite is about to announce a new housing series with larger port within the next month, supporting the 11-24 as well.
Might be a more affordable option. I am still not sure if I should wait and see or go with the Nauticam straight away (which in my opinion is the better option, if you can afford it), due to a tight budget at the moment...