I just completed this 53ft drop deck beavertail tri-axle trailer today. This is only the second beavertail I have built, the first one was 3 1/2 years ago. They are just much more time consuming, so not sure when the next one will be, maybe another 3 years lol!
Here is a link to the page with all the pictures. https://customrctrailers.com/new-53-beaver-tail-drop-deck-tri-axle-w-ramps/
It is available for sale. Email me with questions, if you send me your zipcode I can get a price with shipping.