@regis you are my hero! Very nice lead here. It took me a while to grok the output types but I was able to make it work.
To start, after more research, I determined that what I was looking for was nested/subsection templates, which is not available.
So what I did was configure my config.yaml:
outputFormats:
Details:
path: details
mediaType: text/html
outputs:
taxonomy:
- HTML
- DETAILS
- RSS
And then create a /layouts/authors/author.details.html
Boom. I now have /authors//detail/ created for all authors! However, at this point, all taxonomy terms have a detail. No matter, I then created a /taxonomy/taxonomy.details.html which simply includes my 404 message, which I also extracted to a partial. 
(pardon my French here)
Much appreciated! Very clever trick to keep around while developing with this amazing tech. 