Hi Steve,
I don't have a precise answer to your question, but the Galaxy CiteULike archive might be helpful here. Any paper that uses, extends, or references Galaxy gets put in that library. Papers are tagged with
one or more of 17 tags. There aren't specific tags for "defines and publishes a workflow" or "reuses a previously published workflow" but I'm pretty sure I've come across many papers that do this.
A good place to start though would be papers with the
shared tag: Papers that have published/shared workflows, histories, datasets, pages, visualizations in a Galaxy instance.
Also, not sure if
CloudMap qualifies here, but if it does, many papers that reference it are reusing the pipeline defined in it.
Hope this helps,
Dave C