Kensington Orbit Trackball
This came out in 2004.
This one is Star Trek looking. No scroll wheel. 2 buttons only.
2 Buttons. Require the software TrackballWorks to customize buttons.
though, someone used this trackball to play the game osu well!
for osu game, see Efficiency: Mouse vs Trackpad vs Touchpad vs Joystick vs Pen Input
Light Mod
Ball Size
Ball diameter: 40 mm