Is it possible to customize HS.UI.Registry.User.Find?

I've written several custom classes to add additional search capabilities to the user / clinician search defined in HS.UI.Registry.User.Find. I've tested it out, and it looks and works how I'd like it to, but I've run into a snag when trying to implement it.

The documentation for registering custom user interface pages shows a table of about 50 configuration registry keys for UI pages, but it only lists:

• \UI\Registry\User\Add
• \UI\Registry\User\Home
• \UI\Registry\User\Individual
• \UI\Registry\User\Manage

"Find" is not included in the table, so I guess my first question is whether this table is comprehensive. Are these 45-50 pages the only ones that can be replaced through the configuration registry? This would seem to be the case, since adding a new key for \UI\Registry\User\Find with the name of my custom class for its value is not currently working. 

The only way I've been able to implement this change (for testing purposes) is by temporarily modifying the name of the User.Find class that's hard-coded into the JavaScript method "popupUser" in HS.UI.Util.cls, but this is not the route I'd like to pursue. I'd also thought about customizing / replacing the 10 or so UI pages that call popupUser at some point, but at least half of those pages are not in the list of configuration registry keys either. Is there a way to implement this change cleanly without modifying an HS.UI class directly?