No, there isn't... Sorry. I know Richard posted about making a video on this about 3 years ago, but I think it was pretty far down the list.

I don't know what you searched for, but there is an "alright" article on customizing it in the MS help here:

Customize the Navigation Pane

The Nav Pane is really only for you as the developer. You will shut it off or disable it for the end user, so I don't spend a bunch of time making changes there. Usually, there are way more things I'm wanting to do in the db and forms that are more important to me. If you use good naming for your objects, they naturally group in the standard or default configuration anyway. But to each his own.

Hi Scott, As usual, I had to spend about a half hour tinkering with it to finally get it. I've gotten to the point where there are so many tables and forms, that I had to spend some time "compressing" what I was seeing in the navigation pane. All the names tend to blend together, especially on a small laptop screen. Cheers