PVC Pipe Aeration.pdf
How about using a simple air compressor and some PVC pipe with small holes drilled into it. You could run a section of PVC pipe without holes in it say 100 yards out into the lake. Then have another section of PVC with fine holes drilled into it that would allow a limited amount of air to escape - similar to a garden hose with a fine spray of water coming from it. The PVC pipe would be hooked up to an air compressor which would pressurize the system with air and release small amount of air down the section of PVC with small holes to regulate the amount of air escaping from it. The PVC pipe would need to be anchored to the bottom of the lake to hold it from floating to the top.
If this regulated air escaping was to be released into the water at say 20feet of depth, I think the air would naturally filter through holes in the ice similar to the natural carbon dioxide being dissolved in normal lakes. The air would be released to dissolve in the water, and I think the water would still freeze over solid if the section of PVC pipe distributed the air over a large enough area.
Tests would need to be conducted to see what amount of air could be released into the water that could naturally be filtered through the ice, while still allowing the water to completely freeze over, thus eliminating any open water.
See quick illustration for the picture I see in my head.
Not sure if this solution would really work, but food for thought for you all.