Me too!
Don't know if you're still around but if you are, or for anyone else who stumbles on this as I did ...
This is exactly what I wanted to do with the HTML lyrics viewer I was hoping to make.
You can see the result here:
My Export to HTML Configuration (for Viewing Lyrics)
I used Javascript to collapse all the tracks and albums. Clicking on any of the elements makes the content deeper down toggle visible or not.
MP3TAG won't write the Javascript for you (as far as I know now); so I what I did first is write a very basic web page from scratch that set up a nested set of elements (artist, album, track) which I could later use MP3TAG to generate from my music collection.
Using VERY basic javascript and css, I managed to get the template working in an acceptable manner.
Than I just figured out what parts I needed to get MP3TAG to fill in. For example, my working HTML template just said "ALBUM NAME #2" or "TRACK NAME #5"; and I had to figure out what to put into MP3TAG to get that data as output.
I set up my desired track sort order via a nested set of $Loop() commands; and decided which tags to use as my output.
I had a few snags figuring out the correct way to feed some special characters required by the javascript through the export loops; and also a few others figuring out how to do some on-the-fly manipulation of special characters in my output strings so they didn't mess up my javascript links.
But the online documentation is excellent, and eventually I got it all working.
I still could do a lot to make it "prettier" (and probably I should show more data on the track level that I didn't feel necessary the first time around, like track time, bit rate, genre, etc.) and put it all in a nice pretty grid ... but I wanted something very lightweight and functional to start.
I'm truly amazed with this program. It's the perfect compliment to someone as OCD as me.