I intentionally left the top looking like a "ramp" to the top tree from the backbone.  Adds a bit of character I think.
Here, I tacked in some slugs to the botton part of the frame to lead into the hard tail.  Figuring this frame will  have about 8" stretch in the down tubes, and another 8 - 10" stretch overall length-wise.  The Honda frame is about 2" wider than the HD weld-on, so the bottom tubes will have to curve in slightly to mate up correctly.