I don't have the equipment to experiment with this at the moment, but wouldn't it be possible to capture and retain much of a sugars flavor in the final beer by mashing low, then cold crashing with your sugar of choice and finally force carbonating? This would require some experimentation in order to yield a balanced brew, of course. I'm thinking about this in terms of different types of honeys and syrups which lose much of their complexity as the yeast ferment them.