Is there in existence somewhere, or is there any plan to create a heirarchial, hyperlinked, searchable API reference?
do you , by any chance, mean THE api reference?
https://www.panda3d.org/apiref.php?page=classes note you can list classes, methods, and functions. using the search function of your browser should bring you to where you want to go to.
also, there’s pydoc. in the command line type pydoc -g
The page you are looking for is this one:
panda3d.org/manual/index.php/Class_Reference
That one is both hyperlinked and ‘heirarchial’, as you requested. 
you guys rule