Doing more research, it looks like it requires a Cornelius keg and a bottle of 75/25 CO2 and Nitrogen. Some of our local restaurants are converting to this instead of by the bottle. I may have to give this a try but would still like to hear from any others who have experience with this.
I've not see the kegs the wineries are using. I have used corney kegs for my wine and for topping with good results. I would not use any CO2 for fear of carbonation. I use argon and understand nitrogen is more common flor wine. There are 2 - 3 gal corney type kegs.
The story I have read on the wine kegs is that you use a blend of 75% N and 25% CO2 and only pressure it up to 3-5 psi, they claim it will not introduce CO2 to your wine at that level. I will purge the cornies with straight argon, but once the restaurant receives them, they have the N/CO2 tanks in place for their delivery system.