Hm. Interesting. I went through each of the 3DS eShop menu groups and typed out each game available.
Tennis
Fortified Zone
Alleyway
Baseball
These four don't seem to be listed in any of the groups - but you can find them by searching for them or digging through the entire list. Weird.
So, to go back to my numbers...
If you've had your system since launch, you should have
21 Ambassador Icons
5 Free Downloads (Including Four Swords - 112 of your DSiWare Blocks)
13 System Icons
20 Free Video Icons (including the three new videos)
That's 59/120
There have been 38 titles released for exclusively 3DS - ExciteBike, 34 other games... and the 3 Dreamworks Animation videos...
That would bump you up to 96/120, meaning you'd only need 25 DSiWare downloads.
To do this, I'd need to spend nearly $125 (~$80 more than I currently have in credit).
Then, I'd actually have 122 titles (I currently have 26 pieces of DSiWare on my system).
Who wants to send me $80?
Oh yeah, the 15 minutes I spent on this was totally worthwhile.
Let's not discuss how much time I spent playing with all of this.

I wish Nintendo would borrow from the PS3 UI design for their channel setup. For example, if you were to scroll to the right and find a 3dsware channel, you'll then have your game channels listed under that. Scroll again to the right and you'll have a channel for NES games where you then scroll up and down through your list of titles. You'll still navigate from left to right as it currently is set up but stack everything into sections that you can navigate through up and down. It'll make it a lot easier to find a specific game especially to those who are really stacked on titles.
While I'd love to see more options for organizing the games, I don't care much for this particular suggestion. I like being able to group, say, my Zelda games together... even if one's an NES game, ones a DSiWare title and ones a Game Boy Color game.