I was trolling the kensington site and saw this.
Looks like an improved version of the orbit.
http://us.kensington.com/html/17531.html
not quite available yet, hopefully soon.
It has a scroll ring, but looks to be two button. They should have went the extra step and made it four buttons.
They already have a four button trackball with scroll ring though. With this thing at a price point of $40, if it had four buttons it would cannibalize sales from the pricey (and presumably profitable) Expert Mouse, or it'd have to cost more, leaving that market segment uncovered.
Having a scroll-wheel-less Orbit at work and an Expert Mouse Pro from a few years ago, I find that I don't really use any of the extra buttons and could get away with only two buttons on my Expert Mouse Pro much more than I would ever need a four-button Orbit. I don't even use the scroll wheel on the bigger trackball.