Well, here we go. My little brother, with the help of friends, built most of the standard LEGO "wall" that sat on top of the DUPLO bricks. Then, I implemented the coin-manipulating device. However.....now I'm going to have to find a way to cover the device (but leave the bottom two-thirds of the machine open so the products can be seen). We're running low on standard LEGO bricks here. Perhaps I should take out some of the standard LEGO bricks and put in those other DUPLO bricks to compensate for the loss of height.
I added a side door so that the coin holding device can easily slide out (and hopefully take the coins with it)
Additionally, I hinged a section of the top of the machine to allow for access to the bucket-rotating motor and this NXT Intelligent Brick's motor port and USB port.