DavidSW has a 126603 listed for sale at the moment. I’ve never purchased from them personally, but hear them mentioned a lot on the watch forums I checkout every now and then.
https://davidsw.com/product-category...x/sea-dweller/
I checked watchfinder out of Toronto, however they don’t have the specific sea dweller you are after. I see they have a 126600 with the red text which is pretty cool.
https://www.watchfinder.ca/shop/watc...n=0&max=300000
Both of the above are grey dealers. Getting any of the professional models at retail is very difficult unless you have a pre-established relationship or find a dealer that is willing to put you on a list and then patiently waiting for the call which could be months or even years out, unfortunately.