John, it's way too easy to get Secondlife to open a second instance. all you need to do is go to .secondlife/logs and rename the file SecondLife.exec_marker to anything you like. SecondLife.exec_marker is used by secondlife to determine if there is already an instance of secondlife running.

.secondlife is a hidden directory so you will need to check the Show Hidden Files option in the filemanager's view menu.