I think this would work for your cone. Someone would have to double check me on this to make sure I'm not missing something. Been a while since I've done this.
Lets say you have a cone with a radius of 1'-6" and a height of 5'
I would draw a circle with a radius of 1'-6". Do an erase partial and snap to the same point three time to break the circle into a arc. Then use Measures, Arc Length to get the length of the arc, which is 9'-5 3/32". I would then draw a 5'-0" line. Then I would go into Curves, Curve Data. Set the Radius Point To one end of the line. Then set Start Point to the other end of the line. Input the Arc Length as 9'-5 3/32". That should populate the remaining curve data, and then click the Add button and the curve should be drawn. Then connect the last gap with a line.
For truncated cone it's similar, but you figure both the top and bottom arc lengths, and reverse the start and radius points of each.
For more complex polygon based shapes I would probably explode into polygons, recolor for easier tracking, and manually 3D rotate the pieces to build the flat shape.