I had initially thought I would put some thermal paste under them and bolt them onto the case bottom. However, since I had some spare parts to do better than that I decided to opt for something a lot more robust.
I had some spare heat sink material and I have a lot of spare computer fans around so I decided to try to mate them up and build to identical heat sink setups for each set of diodes. Each bank of 4 supplies in this (there are 2 banks) has a dual diode at the end before both banks merge into a single output. This is to keep their output separated from each bank.
So here are some photo's of what I came up with. I still have to apply the new thermal paste under them, and make some new cables to run to the output terminals, but I was able to get things migrated around in the case, and the completed heat sink / fan combos built and installed this past weekend.
These fans blow INTO the heat sink instead of sucking out of them. This forces most of the air UP the fins and out of the case through exhaust fans at the top of the case.