Using a Input Emulator such as GlovePIE you can use multiple mouses using more than one mouse attached to the PC.
It simply creates a second cursor (up to 4 cursors) with a number beside it and uses the other mouses as fake mouses.
Long story short, I wonder if that can be used on local Multiplayer. I don't know much of coding, but I think it won't be more than enabling more than one player to have a mouse on controls page and perhaps use the names they use in the buttons settings, which is simply mouse2, mouse3 and mouse4.
If anyone is interested, I used the MouseParty.pie script that comes with the software. By the way, it's a freeware software.
I hope it can help people without joypads (my chinese Multilaser isn't seen by Mari0) before we have online multiplayer.