I currently have a total of 68 games on mine (counting the original 30), so it looks like you can go beyond the limit.
If you use the tool from
http://clusterrr.com/soft/hakchi2.zip, it's extremely easy. No save states or any of that other crap needed. Just run the application, add games/boxart (it even searches google for you), then follow the on-screen instructions to flash the system and then you can dump games with ease. I'm not even sure if this is needed every time, but I turn the system on in dev mode (hold reset for a few seconds, then power it on) when I'm adding games.
The only issues I've run into are:
-Some games are titled incorrectly on the game selection menu
-Some games are out of alphabetical order
-A few games would not add themselves to Hakchi when I tried. Could be the ROM dumps. One of the games that wouldn't add was a translated rom of Kid Dracula.
Since Nintendo can't do anything to stop this, watch them re-release the Mini with a different power port something done to stop this kind of hack from happening. Then the price of the original units will skyrocket.
