[aerohead]

I don't think you'll want to consider air conditioning the car's cabin with ice.There are many sites online which will explain refrigeration and air conditioning.Load,tonnage,horsepower.etc..
A car's AC can use as much horsepower as that of a 1-bedroom apartment.Remember,you're driving an uninsulated solar greenhouse during daytime hours,with high humidity.
You might consider something like a 'cool-vest' which jungle helicopter pilots and NASCAR drivers wear .They just cool the torso and blood.
Nothing will keep you as comfortable as refrigerated air from an air conditioner.
You can create this effect with a chilled water system,but you need to consider the thermal load.It's the reason we have compressor-driven refrigeration cycles in cars.