I had an interesting dish at
Movida which was a thin slice of baguette, toasted until crisp, with a rather strong anchovy laid across it (somewhere between the boquerones I'm used to and a salt-cured anchovy), drizzle of olive oil, and a small quenelle of tomato sorbet. Interesting textural, temperature and flavor contrasts all in one bite. Might be worth considering...
As to the textural benefit of sugar in sorbet and ice cream, I remembered reading an entry in On Food and Cooking from Harold McGee which covered this. I managed to find the box (still unpacking) that had my copy and found this:
On Food and Cooking/Harold McGee wrote:The more syrup and plant debris there are, the more the solid crystals are lubricated, the more easily they slide past each other when we press with spoon or tongue, and the softer the ice's texture. Most ices are made with about double the sugar of ice cream (whose substantial fat and protein content helps soften the texture, p. 40), between 25 and 35% by weight.
...
...purees rich in pectins and other plant debris (pineapple, raspberry) require less total sugar for softening. Many cooks replace a quarter to a third of the added table sugar (sucrose) with corn syrup or glucose, which helps soften without adding as much perceptible sweetness.
Based on that, I'd say it would be worth thinking about intentionally including "debris" in your mixes, so purees not infusions. Also, looking at the inclusion of sugars which are less sweet tasting (which - again per McGee - would be ones like Maltose and Lactose). Using emulsifiers to incorporate fats in to the mixes could also work well to smooth things out.
As to d4v3's suggestion of considering stabilizers/hydrocolloids, you might want to check out
Texture - A hydrocolloid recipe collection from
khymos.org which contains recipes for ice creams and sorbets (including savory ones) using guar gum, lecithin, locust bean gum, etc.
-Dan