It is possible to achieve this with a python script. The script requires python-wnck and python-gtk to be installed in order to work, although I think these are installed by default anyway.
Copy and paste this into a text editor and save in a sensible place (eg. switch.py in your home folder):
screen = wnck.screen_get_default()
windows = screen.get_windows()
for w in windows:
if len(sys.argv) > 1:
if w.get_application().get_name() == sys.argv:
print("Application name of window with title " + repr(w.get_name()) + " is " + repr(w.get_application().get_name()))
You can then set up the keyboard shortcut by opening Keyboard Shortcuts (System->Preferences->Keyboard Shortcuts).
Click add to create a new shortcut.
Use the command
bash -c 'python ~/switch.py Terminal' (this is assuming you saved it as switch.py in your home folder). Replace 'Terminal' with the application name of the window you want to switch to. To find out the application names of the currently opened windows, run
python ~/switch.py in a terminal.
You can then assign your preferred keyboard combination to this action.