Picked up a Logitech Cordless Optical Trackman the other day - a fine addition! : r/Trackballs
Logitech Cordless Optical Trackman at TigerDirect.com
Amazon.com: Logitech ERGO M575 Wireless Trackball Mouse - Easy thumb control, precision and smooth tracking, ergonomic comfort design, for Windows, PC and Mac with Bluetooth and USB capabilities - Graphite : Electronics