I worked on three different trading floors in the US over a span of years. In naked shorting all they have to do is keep changing the seller's give-up name with trade breaks and keep the name-changing merry-go-round going round and round until someone at the clearing corp blows the whistle. In naked short activity, they may even know someone at the clearing corp who ignores everything until the buyer demands his physical securities.

When I worked on transaction problems, a member wasn't confirming one side of the trade for whatever reason. I believe the clearing corp would have totals on open trades but I have never heard that they ever published them. What they would do is notify a member of a persisting problem that needed to be finalized. The easiest solution for the naked seller would be to change the seller's give-up through one of his buddies.

So, there doesn't appear to be an entity that would publish suspected outstanding naked short totals IMO.