I'm also affected by gnome-panel never showing up. Others on the Linux Mint Forums report the same issue: http://forums.linuxmint.com/viewtopic.php?f=141&t=70230&p=449031#p449031
The severity of this bug needs to be raised as it makes Gnome unusable. notification/systray is on the panel (inability to get to things like network manager, CCSM, laptop battery monitor, etc) menus depend on the panel (Gnome unlike other DEs doesn't utilize right-click-the-desktop menus). Applications can only be launched by ALT-F2, and whatever shortcuts happen to be on the desktop. The current workaround is to "use another Desktop Environment", which seems to warrant this bug having a higher priority than "normal"
