I just got a Stout tap, and I'm using a CO2 tank and regulator that is filled with beergas.
It is hard to get a CO2 tank filled with beergas though. Two places I went to wouldn't do it for me. I finally found a place that would do it. The key is that they don't exceed the rating of the CO2 tank regarding pressure. That way you can still use your CO2 regulator with it.
I even think the Taprite CO2 regulator is actually rated for 3,000 psi or so. The gauge only goes up to 2,000 psi, but even if it was filled with a higher pressure I think it would just pin the needle all the way, but still not harm the gauge.
Only reason why I went this route was because I already had a new tank and gauge, so instead of having to buy a steel nitro tank and nitro regulator, I found a way to use what I currently have.