Rob: does a retractable hard top sound do-able?

        - Mike
 
For sure and this type of thinking is a great way of combining space with performance.  Making it variable height as well adds some complexity, but with telescoping f'glass tubes, would not impinge on space inside.  Removable, rather than retractable might be easier, and a series of slats held together with flexible material  (I used 1" wide cedar strips glued to dynel painted with 2 pack pu for a curved hatch on harrigami; worked very well) would allow it to be rolled up, which might be easier again.