In a blast from the past, Logitech releases a new trackball
arstechnica.com
arstechnica.com
Much more convenient to use with laptops, or with setups where wires are inconvenient for reasons other than mobility while in use (e.g., any situation where you would use a wireless keyboard, which is also usually stationary when in use.)
I've had a wired Logitech trackball for many years, and I worry that on the day it breaks I won't be able to replace it.