The stillborn Triking-Morgan commissioned by Merz und Pabst - and abandoned after only one had been half-built - was designed with sliding pillars (er, or not exactly). I have been told (by people who should know) that the sliding pillar "would never work" on the modern three-wheeler, one reason being that it would be too heavy.
It would be interesting to know what has become of this intriguing Guzzi-powered machine. I understand that it is now somewhere in Germany, perhaps gathering dust in the back of someone's garage. Triking actually supplied a double-wishbone front end for it as a replacement for the sliding (or not) pillars that were judged unsuitable.
