Bit more work before bed, riveted in some more reinforcing sheet metal and started adding the top frame legs. The PSU support is now riveted/bolted into place as well, as well as having a bit trimmed so that the psu can be mounted flush. One more leg to go, a bit of fab to make an additional braket to mount the psu, mount the cage, and a bit of fine tuning to make everything secure, and fab should finally be finished.
What are the dimensions of this ammo box you have? I'm wanting to use the same sized mobo and hardware you are, but I can't seem to find any boxes big enough for it.