If you would like to try making a prototype of this drive base you could make some cheap "omnis" like the ones we used on this prototype base. We just got cut a slit down a piece of some blue pool tubing (I think it's used as electrical conduit). Then, we just ziptied it around one of the KOP wheels. They aren't pretty, but we used them through at least 10 tournaments with zero problems. Plus they were way cheaper then buying real omnis and worked almost as well for our application.
http://img155.imageshack.us/my.php?image=wheelshq2.jpg