One bit of trivia on the Solstice coupe - it would have been a true fixed head coupe, except that the safety approval process would have had to be redone at considerable cost, so GM opted to use a removable top panel, which sidestepped that expense.
Unfortunately they bodged the design of the top by not making the panel that you remove storable behind the seats so they offered a collapsible soft top that would stow there, but not well. Today the soft top changes hands for around $2K as not many were made (I bought my coupe new off the lot but didn't want a soft top - I'd have preferred the hard top to be welded to the body!)
Changing the top (an amusing video):