Limit Promotion Redemptions

Is there a way that I can setup my promotions so they can only be used a certain number of times instead of having them expire on a certain day.

For instance i want clients to have a 100.00 off coupon for images but after they use it one time it becomes invalid. Otherwise they can check out over and over again with the same code and get all the downloadable images they want for free.

Maybe create a variable for the promotion uses and each time its used the counter decrements on the variable by one. Then the condition part of the promotion will do a check against the promotion uses variable and if its greater than or equal to 1 it will work otherwise it will not.

This may be something that be put into another version or I can try to add it to my current setup if it would not be too hard.