While an interesting idea, I agree with Guitarist that the person with the biggest storage area will win. If the contest started tomorrow, I'd go to Sam's Club tonight and back the truck up. The contest would need to be of a long enough duration that storage wont factor in, if that's possible.
I think it would be far more interesting if the competition was "Spend only 50% of normal for 3 months" or something of that sort. Ignore the bills that can't be lessened (mortgage), but include everything else: groceries, phone, fuel, gas/water/electric, entertainment, etc. I think it would give you a healthy view on what you can live without and let you appreciate the things you spend your money on more.
Then, when the challenge is over, only go back to spending 75% of normal and see how you feel about that. The 75% mark may feel very comfortable to you after the 50% mark and you'd still be saving 25% more than normal. Then rinse and repeat.