Interesting idea! An aerial tram might actually be quite practical. Not too expensive to build, potentially aesthetically pleasing, and such a spectacular view that visitors (i.e. non-Fast Pass / non-Clipper / non-transfer passengers) would happily cough up $5 a pop for the ride. Might even be a money-maker.
Similar systems:
http://en.wikipedia.org/wiki/Portland_Aerial_Tram http://en.wikipedia.org/wiki/Roosevelt_Island_Tramway