78 CJ and Wrangler are not the same at the tub dimensionally). Parts Mike (enter it just like that in your search engine) will get you stuff for the conversion. It will cast some bucks, though. I think you and I are in the same boat. If I can't come up with the same year hardtop for my application, then I am going to use JC Whitney's body panels and weld in a side profile like a 76 CJ. Then I'll buy the 76 hardtop which seems to be a bit more common.
Jeep's 'R Made 4 Changin' (& Changin'& Changin'...)