Kind of Guzzi related;

Have to wait till almost the end till they mention where the engine comes from.
.
[You must be registered and logged in to see this link.]
.
[You must be registered and logged in to see this image.]

I want something like this when I lose my ability to keep a bike upright.

This is the 3-wheel version: [You must be registered and logged in to see this link.]

[You must be registered and logged in to see this image.]

These are made closer to home with the steering wheel on the correct side.
[You must be registered and logged in to see this link.]
.
[You must be registered and logged in to see this image.]

Someone in my town has one, I see it every now and then.  Drive train is all GM and all parts can be purchased in the local parts store.

Yes. Not as classic looking but probably the better value. The Cycle Exchange sells them new for $39K though they do have this used one for $24K

[You must be registered and logged in to see this image.]