Gordon, as you said above
We really need something that is "just right" thickness-wise so it can thermally connect the CPU to the case. All that lovely machined case is just waiting to help as a heat sink!
If you are going to sell more Slice boxes, with the CM3 rather than the CM, I would have thought that y'all will need to supply a heat sink for those.
If so, maybe you can make a few more amd make them available for the "early adopters" who have upgraded to CM3, to purchase??