You can clone with
I'd like to be able to mock out an object created via new. Perhaps something like
var i = new Image();
i.src = '/some_url';
var c = new Vehicle.Car();
I might also imagine being able to access the original definition of the "class" (function) via StubbedFunction.originalDefinition.
Your latter example can be done with jasmine.createSpyObj - you can create an Object with a bunch of spies as functional properties. We do this a lot in our testing.
Your "instance" interface looks interesting. Why not test-drive the concept and see if you can get some traction?