These guys’ service is awesome, I’ve purchased from them a few times. That being said, we recently switched to an Exped MegaMat and couldn’t be happier.
There’s a guy in the Chinese diesel heater Facebook group that was 3D printing some fittings for portable boxes that would probably work in your wall. I’ll see if I can find his info and message it to you.
I think this thread over at Tacoma World has drawings of the original hood pins that you could take to a fabricator and have made up. I’m sorry I’m unable to find the specific post.
https://www.tacomaworld.com/threads/the-flippac-info-thread.569656/
Will fit 2nd and 3rd Gen Toyota Tacomas.
Served us well for many years and countless nights.
https://www.tacomaworld.com/threads/diy-raised-platform….562000/#post-18424905
The rear piece of the platform was cut to make room for bed stiffeners.
Pad is not the IKEA one mentioned in the post...
Similar setups in a Flippac were rated to 160lbs (I think) and were made of metal, but I’m not sure if the limiting factor was the metal or the fabric or the attachment points. With that additional leg, yours looks more robust.