Definitely on the right track....
I recall my grandma making Banana Ice Cream when I was a kid, and one of the factors that would make it the best is to wait till the bananas are banana bread ready... In other words, wait till there's not really much yellow left on them, and let all of the sugars come out, because that's when it seems that they also have the most fragrance too. One thing that I remember was that grandma would add a couple drops of Almond Extract into the mix, because it would help increase the fragrance of Banana, and also just adds a nice touch. I think she also didn't put quite as much vanilla into the mix as she would had she made Vanilla Ice Cream, and she never added any with Chocolate.
I think if I were to make my own Banana Ice Cream today, I'd make it with 75% over-ripe sweet dessert type (maybe Grand Nain, Goldfinger or Iholene - those have a really good fragrance), then 25% tart dessert banana, like Manzano for more texture and spectrum. I'd also add the tart one just a couple minutes before finishing so there's little pieces of banana left intact to enjoy.
This is just my humble opinion, but I'd bet it would make great Ice Cream...
BTW - you didn't invite me for some scrummy Pistachio Ice Cream??? Ahk!
