If you save this script as gnome-launch-box-startup.sh, you should be able to bind a key to the script using gconf-editor (e.g. /apps/metacity/global_keybindings/run_command_1 to gnome-launch-box-startup.sh and /apps/metacity/keybinding_commands/command_1 to <Alt>space).
By the way: I guess making a script that kills gnome-launch-box before it launches it again would be a quick workaround.
#!/bin/bash
killall gnome-launch-box
gnome-launch-box -t
If you save this script as gnome-launch- box-startup. sh, you should be able to bind a key to the script using gconf-editor (e.g. /apps/metacity/ global_ keybindings/ run_command_ 1 to gnome-launch- box-startup. sh and /apps/metacity/ keybinding_ commands/ command_ 1 to <Alt>space).
Haven't tried it though.