Morning John,
Yup I'd guess there are pros and cons... It sure would be responsive in the twisties!! On the down side it would also be a bit twitchy on the strait roads. It wouldn't take much of a rake kit (if one is even available) to make it almost unrideable.
I disagree about the looks. It would be one sporty little rascal!! Sort of like one of the "Match Box" cars. Didn't mean that as a negative at all... If you do this please post photos....
My Motor Trike Adventure is the shortest and narrowest conversion for a GL1800 it's really great in the twisties but still behaves on the open road.