As far as we know, the Sidekick 3 was the first big mobile device to come out with a trackball. (No, that old Powerbook doesn’t count, you know what we mean) One of our readers pointed out the BlackBerry Pearl that was officially announced recently. We headed over to Gizmodo to check out some good pics of it. It looks way too similar to the trackball found on the Sidekick 3. We’re just speculating at this point and I’m no lawyer, but I wonder if Danger has any sort of claim to this. We all know they’re patent lawyers are all over the signature screen flip. What about the other aspects of the device?