I've made a very robust app switcher using wmctrl. Check my Ubuntu Forums post and my askubuntu answer.

This is the script to launch:

#!/bin/bash

app_name=$1

workspace_number=`wmctrl -d | grep '*' | cut -d' ' -f 1`

win_list=`wmctrl -lx | grep $app_name | grep " $workspace_number " | awk '{print $1}'`





active_win_id=`xprop -root | grep '^_NET_ACTIVE_W' | awk -F'# 0x' '{print $2}' | awk -F', ' '{print $1}'`

if [ "$active_win_id" == "0" ]; then

    active_win_id=""

fi





# get next window to focus on, removing id active

switch_to=`echo $win_list | sed s/.*$active_win_id// | awk '{print $1}'`

# if the current window is the last in the list ... take the first one

if [ "$switch_to" == "" ];then

    switch_to=`echo $win_list | awk '{print $1}'`

fi





if [[ -n "${switch_to}" ]]

    then

        (wmctrl -ia "$switch_to") &

    else

        if [[ -n "$2" ]]

            then

                ($2) &

        fi

fi





exit 0