I've still got two Trackmans (Trackmen?) that I use. My mother has that wireless model Dusty linked to and while it's close, it's not quite the same as Trackman when it comes to how it feel in your hand (button placement, trackball feel, etc.). While I still preferred Trackman, the wireless model wasn't bad, though YMMV. I use Kensington Expert Mouse as my main trackball, though that thing not something I'd carry around with my laptop.