This is a real important topic. Lots of us are on sugar restricted diets. I have been working on this for a couple of years. I use the Jeni's cookbook recipe as my basic cream mix (it uses 1T plus 1t of cornstarch for each 4 cups of milk/cream, added at the end and boiled for 1 minute more) I've succeeded at reducing the sugar by half, but my family wasn't happy when I went to zero. Here's what I've learned:
For sweetness: My wife objects to stevia, so I have settled on this formula: Substitute 1/4 c xylitol plus 1/4 c erythritol for each 1/3 c of sugar in the recipe. I added three drops of Stevia liquid. Recently I found a product called LC-White Sugar Sweetener with Inulin. It's very expensive, and I've not yet tried it.
Jeni's calls for corn syrup, which violates the rules. I have tried lecithin and glycerine, one for one with the corn syrup, and that seems to work. The lecithin feels weird going into the mix.
Other ways to get scoopability: Cornstarch is one. I eliminated the 2/3 c sugar in teh Jenis recipe and kept the cornstarch and it was scoopable. BUT, that recipe kept the 2 T light corn syrup. I have a sack of poly-D fiber in the pantry; it's supposed to work but I don't know how to use it.
I have used Cremodan, which seems to be a mix of several thickeners, and it definitely works. It is hard to get it to go into solution, however, and I've never figured out when it goes into the mix and how to do it so it dissolves. I've had to resort to a hand blender to get it broken up. If the rules of the forum allow you to send me your address I'll mail you some Cremodan and you can try it. The big can I have will last me a lifetime.
I have seen references on the web to using Inulin and poly-D fiber. I haven't been able to figure out how much, when to put it in, and exactly what it substitutes for. I've not found a recipe on the web that uses either, so I don't know quantities or how and when to add it.
I'm really glad to find someone who's working on this. I'd like to help any way I can (after an ice cream contest in June, that is. I'm going with sugar there)