Sounds like the version I make except I usually add some type of stone fruit like peaches or apricots. I also either include some simple syrup or use 7-up for the fizz to sweeten it up a bit. After your done with the drink add the fruit to vanilla ice cream......
The ones that we have had at the lounges in Disney are good but they are made using a sangria syrup mix added to wine without the addition of brandy. If by blended you mean with ice like a frozen margarita I have not seen this at WDW.