Is there are a way to see what's taking up space in very large .ompl file / Dynaline File?

My DynaList has been especially SLOW - lately on every platform, -so I’m guessing it is that I just have too much stuffed into one File. I am making an Archive File and moving stuff out of my Home file to make it not such a huge file.

The OMPL file is isometric to a file-system structure. There are apps that let you see where you are using all your disk space. I was wondering if there would be a way to cobble together a way of doing this for an OMPL file.

Here are some images of apps that visualize and make it easy to find where the most are taken up in your disk space.

Imgur album with examples:

Any ideas? Has anyone created something like this before, or will I have to make it?