It is a great idea.
In college I had a professor come in and give each group $20. He then said, make as much as you can out of this by the end of the week.
It was a great exercise.
We created superbowl t-shirts and made almost $100 bucks.
The key to the competition though is a short time frame. I think if you make it months, it would not work. It would have to be weeks. One week worked great for us.
A group is key as well. Doing this alone might lose its edge because you lose the motivation that teammates give you.
Just my .02 though.
An entrepreneur tends to bite off a little more than he can chew hoping he'll quickly learn how to chew it.