Since I'm going the meanwell route now, I removed the DC-DC and all it's glory out of the car today, as well as the frame I had started constructing for it.
Current plan is to integrate the meanwell into the "design" of the rear, i.e. not make it obvious and out in the open, yet maintain decent enough airflow to keep it cool. I have an idea on how I'm going to accomplish this, but it isn't set in stone yet.
I repurposed the aluminum support bar that was underneath the IMA box and will be using it to support the meanwell psu. I could've made an aluminum support bar but for the fanciful idea that the aluminum bar will help with heat dissipation some. Attached in existing holes. Measurements of the meanwell are less than 9"x5"x3" so it should fit fine in the area to the driver's side of the fuel tank.
Vacuumed out the rear and began to lay underlay, but then it started raining so I stopped for the evening. Current plan is underlay, foam board, underlay, plywood, underlay, carpet.
Progress so far:
Hopefully it isn't raining tomorrow before I go into work so I can make more progress.
Meanwell and rectifier arrive Thursday.