Pi 3 with Dual Trackballs? *Anyone* have this working?

[Afterburner]

Got a Pi 3 Model B today.

Giving serious consideration to using it to replace the 14 year old PC that is currently running my full size MAME cab.

The PC is running an AMD Athlon XP 1600 with 1GB RAM.   I have to believe the Pi 3 can pretty much run anything I'm currently playing on that old PC.

My joysticks are 8-way rotary microswitch types connected to a really old IPAC keyboard emulator.  I don't expect any issues there.  Should be able to just recognize it as a USB keyboard....I hope.

But one thing is giving me pause.  My current cab has a 2-player CP and I'm using dual X-Arcade USB trackballs.  My son and I play a lot of games together (cooperatively) that use dual trackballs and not being able to get both working is a non-starter for me.

From the reading I've done here and other places, it appears that getting two USB mice recognized by the Pi is very iffy.  Does anyone have this working successfully, or if not dual trackballs, at least two devices that are both recognized as USB mice?