@okiecamper. Good to know it's been done before.
Do you have any pictures that you can share? I'm curious to know what types of screws you used or if you have any tips that you can share as I'm not particularly handy but am willing to try doing it on my own.
I started breaking down the top bunker and it looks pretty straight forward to re-size so I can raise it by 12" and use it as a narrow shelf. It looks like they cut out the wall panel on the bathroom side to fit the frame; hopefully it's not like that all around.
My primary concern at this point is securing the shelf but based on other posts I'm assuming there will be something for the screw to grab into.
Adam