Ta-Da! We have a functioning shooter!
Video:
http://youtu.be/DASvBTc78GM
We're getting 20-30 feet from it with stacked wheels (as you suggested), two different CIM motors, a big one and a smaller one, the smaller one spins faster than the big motor, which apparently gave us the variance we needed. However, it was a little bit accidental, we put it all together and said "Let's see if it works!" and it worked fantastically! We also increased our compression and added some foam insulation tape for friction, which helped a lot.
Thanks again from the entire team, we look forward to the Silicon Valley Regional next week!