Two possibilities:
There's a place in Crystal River, Florida, that sells used and overstock hardtops and t-tops, It's called Monroe Sales marine surplus. Whatever they have will require some modification, but the prices are very reasonable. Guy's name is Mac. He can be a PITA to deal with, but he's honest. (352)527-3555
The guy who owns Project Boats website has a Sceptre as his personal boat, and he used to have a hardtop/half-tower on it. He was asking $1000 for it. I don't know if he sold it yet, but go to
http://www.projectboats.net/description.html?1022
He is in the Melbourne, Florida area. (321) 863-1455
__________________
Common Sense is learning from your mistakes. Wisdom is learning from the other guy's mistakes.
Fr. Frank says:
Jesus liked fishing, too. He even walked on water to get to the boat!
Currently without a SeaCraft 
(2) Pompano 12' fishing kayaks
'73 Cobia 18' prototype "Casting Skiff", 70hp Mercury