So pagure already allows you to disable doc/tickets/pull-request at a project level, but it doesn't allow you to disable the main repo.
That being said, you could disable pull-request and doc and just have a README file in the main repo saying what the "project" is about (fesco, FPC...) and just use the issues

That seems reasonable and I'll try it out. I'm just thinking about the use cases which we'd need to accommodate if we were to try to retire fedorahosted. (Which isn't something I'm advocating, but it does seem reasonable for many of the remaining fedorahosted repos.)

(I guess some way to create reports would be pretty much required to replace the FPC use case, at least, but that would be a feature request for the future.)

Could the tags be used to generate these reports?

Feature: you can filter by multiple tags

Hidden feature: if you place a ! in front of a tag it will return you all the tickets not having this tag.

Perhaps; reports are more than just queries since they cover presentation (sorting and grouping) but my use case doesn't really need that. What would be really useful is some way to save searches. I guess currently I can construct a URL by hand and then just include it as a link in the readme file file on the front page.

(Would be cool to be able to have some markup that gives you the number of issues returned by a search, so you could include a count of open bug tickets or something on your front page in the same way that people include the travis state in their front pages on github. But I'm really off topic here, sorry.)

You would also need to have some way of storing / showing a readme file on the overview tab.

This is currently pulled from the README.rst in the git repo. -- maybe these types of projects can still have a repo, just the repo-esque interface elements are hidden from the webUI (if a setting is turned on for that repo or something).

We would also want to consider how to show these types of "projects" in the browse pages too -- perhaps not at all?

So I saw in a search that I had filed this years ago. Thinking about it now... it's dumb. Turning off PRs and such is sufficient and you still need to repo to be able to at minimum upload a file to show on the main page. The only way to go further would be to hide the UI for viewing the contents and history of the repo with the README file, but... I don't see why anyone would waste effort implementing that.