I've created a custom taxonomy 'quote-categories' (a separate category listing for a custom post type) and created a taxonomy-quote-categories.php template that is called successfully when viewing a taxonomy term.
However the page returns no matching post despite there being many posts in that category. I've called that content type successfully all around my site.
The problem was the custom post type did not have the 'public' parameter set to 'true'. Otherwise it is invisible in normal loops and search results.