I see what you’re saying for loading the directories causing a slow down (possibly). However here’s the workflow User Experience I was asked to recreate:
User comes to the site: clicks on directory:
User chooses Parts, services, or rentals
User puts in a keyword to search for and it drops down with a list of the children categories under the parent they’ve already chosen.
User chooses from the list and is directed to a page with all the companies that have that category.
Basically – they have something similar already (http://pesa.org/membership/directory) However your plugin is by far much more aesthetic and you give the ability to edit your own companies and you have so many more, better options (which is why I went with yours). I just need to nail down this search feature and I am ready to put it live for them.
The biggest issue is not having to muddle through the 200+ products before getting to the services category, if that makes sense. I mean one search for all categories can lead to a long drop down… a long long drop down.