This might sound odd, but perhaps you aren't using your ice scraper the best way? I have watched many people not using thiers correctly and thus having an extra hard time removing ice and snow. I find it easiest to turn on the car and defrosts which work very well. Then I get out and test the ice with the flat side of a standard ice scrapper. If I can easily remove the snow then I do. If not then I flip to the other side of the scaper which has the raised bits to create a series of grooves in the ice/snow. The more grooves that you put the easier it is to remove. Then I just remove what's left. If the car has warmed for a bit...you can use the wipers to remove some of the now heated ice/snow or use the now heated washer fluid and wipers. Granted if you do this too early there is potential of causing extra wear of the blades or even the motor if you are trying to move too heavy an amount of ice/snow.
I take a small flower watering pitcher with a nice long spout on it and fill it with warm water. It holds about 10 ounces of water and is usually enough to de-ice the front, back and side windows. Use a towel if it's cold enough outside to refreeze the water before you get the car warmed up. Sure beats scraping the windshield for 20 minutes.
The water trick can be VERY dangerous. I got stuck last year in an apt parking lot trying to get out. Had to get a lady to give me many glasses of hot water. While I could move the car again, the water quickly became ice and caused me to almost hit another car in the parking lot. So be careful if you decide to use hot water. Here they sell liquid ice defroster like the Rain X for your windshield that you put into your window washer or pour onto windshield.