Eric Cheng of Wetpixel posted a great review of the Sea & Sea MDX housing for the Canon 1D Mark III and 1Ds Mark III...
The Sea & Sea MDX-PRO MKIII underwater housing for the Canon 1D Mark III and 1Ds Mark III digital SLR is beautifully machined. It appears to be machined from a solid block of aluminum, and has a nice, smooth finish (flat, black, hard anodizing).
The housing has a leak detector installed, which is a nice feature. However, the detector's battery is mounted dangerously low on the back half of the body. I would have preferred it to be mounted a bit higher so minor leaks don't have the potential to destroy it.
The camera's rear LCD was easy to see through the large plastic window in the back of the housing.
The housing has been cut for an automatic focus light bulkhead, but there is no bulkhead in place. If you use this hole for an accessory bulkhead for any reason (e.g. remote shutter switch), you should be aware that large dome ports will cover the bulkhead and will not allow a connector to be inserted. However, the smaller optical glass dome port does allow access to the bulkhead opening...