could you mean something like more than one game card square, so that when you put in the gateway mutiple game card squares light up, then when its removed they all go blank? And i understand if you like .3ds more than .cia, i do too. half the time i install a cia (or try to) it ends up in some error, or i just cant find the .cia, or something of the sort.
That sounds fancier than what I was thinking of. I was just thinking of a square that was a shortcut to a ROM file on the Gateway card. If the card wasn't inserted, it would give an error and refuse to run.
GW team should be able to accomplish this without too many issues if they wanted to. They already hook into the cartridge functions, from there they would just have to call the correct functions to display a new icon on the home menu, and make the icons launch the correct ROM on the GW cart. They already hook into the title launching functions which is evident based on how every eShop or system title creates a .sav file on the SD card, so if they displayed new icons on the home menu they might be able to just detect that in the existing title launching code in order to load the correct title from the GW cart. If that code doesn't run early enough to manipulate what is launched then they probably know enough about the 3DS to find a hook that does.
But of course they don't want to make it too easy for people to use their work without a GW cart.