I didn’t quite understand the topic way back in the fall of 2015. Now that I have engraved this stamp and looked at other stamps in the office, I know what you are talking about.
The request is for the ability to make a slope from the surface of the relief to the base of the engrave so that each point on the engrave has a wider base for stability. The 3D engraving examples might be the best indication that something like this may be possible.
Here is another topic that discussed the issue of angled cuts regarding dovetails.
There have been many other threads that looked at this option, including one with @dan posting a stepped pyramid to show a layered relief engraving.
I can see how a tapered base would be helpful. At the moment my stamp has a narrow silhouette right down to the bottom of the engrave. Over time, I’m sure those narrow ridges would wear down.