I am currently using an L-Trac without a scroll wheel. I highly recommend investing in a simple switch (a midi sustain pedal will do, or you can make one) to use as a foot-pedal for the mouse
Not only for the purpose of more buttons, but for a reasonably placed third mouse button. I also have an AHK script that will allow you to rough scroll really nicely using the ball if anyone wants it.
You can use a billiard ball.