Malbun
Much as Andorra regularly pays up to host the Vuelta, the Tour and the Volta a Catalunya, it is far from rare that the Tour de Suisse will step across its borders; however trips to France, Germany or Italy are typically rare and the journeys abroad tend to be in the east, either to Austria (Serfaus is a regular stop-off, but going further afield is not unknown - though this year's trip as far as the Rettenbachferner is certainly a rarity) or, quite commonly, to the country's smallest neighbour, Liechtenstein.
When they do go to Liechtenstein, it is almost invariably for a mountaintop finish at the country's fabled ski resort of Malbun. It is a brutal climb whichever route you take into it, and invariably produces some sizable gaps in the GC.
Typically, because of the brutality of the final mountain, the race organizers know that the final climb is all that will prove decisive in the race, and therefore tend to go the Unipublic approach. 2011's stage rather resembled some of the recent stages to Angliru, except without Cordal. In 2007, they came through Austria, but the only obstacle on the way was the Arlbergpass, so this stage was a huge missed opportunity. In 2004, they went one better, producing an espoir-length Unipuerto profile that made baby Jesus cry.
While it is undoubtedly true that a stage to Malbun is likely to see the final climb be the only truly decisive part of the stage, there's still plenty that can be done to ensure legs are tired when they get to Vaduz. The most obvious approach is of course a Triesenberg loop, which amounts to climbing just under half the climb, then descending the other side of it before looping round to climb again. But while a bit of flat is inevitable, there are tough climbs nearby. Take this suggested stage from Sankt Gallen to Malbun taking in Switzerland, Austria and Liechtenstein:
The first 50km, including the initial climb, are in Switzerland; then we detour into Austria. Bödele Losenpass is steep and makes a good route in. The main thing is the link of Furkajoch (and the optional additional climb of Dünserberg) which gives us a tough climb AND a technical descent. The 2007 route over Arlbergpass could have inserted the South side of Faschinajoch:
Before the last 8km of Furkajoch east:
Or, for a different and really tough option, you could go into the same flat run-in to Malbun from the steeper but shorter opposite side of Dünserberg. This would mean climbing the west side of Furkajoch (a legit HC), a mere 2km of Faschinajoch north (at around 6%) then Dünserberg southeast before a similar last 30km to the profile above - so that's these:
Then Malbun as posted above.