You don't seem to understand how exploits work.
It's usualy a bug in a piece of software, that can be exploited with data or files, that the attacker has control of.
You need a way to trigger this exploit, by making the software load your data or file, so it can be exploited.
Now think of the Wii for example.
You had savegame exploits, where you put a manipulated savegame on your system and make the game load this save, so it exploits itself.
Or the bannerbomb exploit, where you put a specialy crafted file on your SD card and make the E-Mail application load it, so it gets exploited.
Or FlashHax, where you navigate to a certain site which contains code, that is able to exploit the Wii's web browser.
You see what they all have in common? They rely on data that you are in control of and that you manually have to trigger somehow.
Of course there are exceptions, like CFWs on other consoles, where the system exploits itself w/o user interaction. But such exploits usualy require a way to run code first on the system, so they can be installed permanently.
Now think of the Wii Mini - you can't control the data that goes on the console, like save games, because it has no SD card slot.
You can't control the data that comes over the network, because it has no WiFi and doesn't care about the network adapter (as long as it's unmodified).
So you try to exploit the only input, that you have control of and see if it works and that's the idea behind BlueBomb.
It sends modified bluetooth packages, which exploit the Wii Minis BT stack to gain code execution on the system.
Now use that info to break it down to your idea - you say "put a file" onto a USB stick, plug it in and it modifies the system.
But how? What is that file? How should the Wii Mini read it? Why should it read it? It's not looking for any files on your USB stick once you insert it, so how should it trigger anything?
Try to understand how things might work first, before you post an idea like this.
The people who create such exploits are experts in their field and are usualy very smart.
If they don't release an exploit, which is as easy as insterting a USB stick with a certain file on it, to exploit a console, then you can be 99.9% sure, that your idea is not realistic.