I am having nearly the exact same issue with my mid-2012 macbook. My mac does a kernel panic randomly when I unplug the Arduino. This is incredibly frustrating for development as it seems the only way I can reliably stop the code/serial monitor and upload a new version is to unplug the usb cable from the Arduino. The Kernel Panic happens randomly somewhere between the 2nd and 10th unplugging of the Arduino. Always on the *un*plugging.
Here is my environment: macbook 2.7Ghz Core i7 OS X 10.7.5 Arduino 1.0.2 Boards: Happens when working with both UNO and MEGA boards
This is a serious bummer and I would appreciate any recommendations if anyone has solved this problem.