Heck if you already have the dado blade, set it wide as you can and just make a cut, put stops at either end. Fast, easy, no additional expense, but not as fancy as the commercial, works just as good. Plus you dont have any excess hanging outside if you wish to ship a bunch of them.
Whatever you do, just be careful, I tried to get fancy and partially amputated a finger, not from the machine, but from kickback and the sharp fresh cut edge of the wood got me just right. Sooooo be careful!