I have been playing with trying to get mame (or a variant) to track both guns at the same time. No success so far.
I've been trying with Analog+ 83.2 (last version with which the analog changes worked I believe. I've had no luck getting it to work at all. Bizarely the triggers on either gun fail to register as anything (and no motion data at all seems to be passed). Not sure is this is my setup or due to something else.
I was thinking that this is essentially like getting dual trackballs to work (which is something else I have been looking at doing anyway) I have a feeling this maybe to do with the fact the guns are NOT seen by the system as mice at all (I'm using the Guncon2 HID compliant driver). It's the Wingun app that is parsing the gun data, and throwing the data at the system mouse. This is why 2 guns work in normal mame for non tracking games (you are both actually sharing the same mouse I believe) but not for tracking.
If thats right, then analog+mame is no help, I think, as there are not 2 mice to see. According to what ErikRuud posted, the EMS Gun2Mouse app does not support 2 guns anyway.
Now Smog's Guncon driver may be different - There is code in AdvanceMame that specifically looks for either Actlabs or Smogs lightguns. However, I have totally failed to install Smogs driver on my system - I can't calibrate it at all, which ends up locking my mouse off screen even when the gun is nowhere near the screen. So I can't control my desktop except the keyboard. I am sure this is something I am doing, as someone posted they had successfully used Smogs driver with this gun.