Request a quote for the MXA3-11-16SSH
The current price is about $200 in single quantities and Fedex overnight shipping is about $30 currently. It takes a few business days for them to manufacture the case.
Of the $200, about 90% of the cost is for machining and 10% for materials.
There is currently no “buy it now” button on their website, so you will have to use Paypal the old-fashioned way.
Check the bottom of your Takachi quote for payment information, such as the specific email address to send Paypal to (you will login to Paypal.com, click Send Money, and type in that email address). Remember to type your invoice or quote number into the Paypal comments along with your name before submitting the payment so that they know who the payment is from.
The person I worked with was Tadateru Sei, who always responded the next business day (usually I sent email at night Japan time, and got the reply several hours later during Japan daytime).
From forum discussions, in coming months there may be easier ways to order, but for now this worked for me.