>>10379417If they were going to go through with something that big, a USS Flagg or a 1/18 Star Destroyer could be on the table. A Star Destroyer that can open up and hold a tie fighter or two inside of a hangar, and have a playable bridge area, would have been a very handsome answer to the USS Flagg back in the day. When GI Joe was at the height of its popularity though, Star Wars was on its way into decline so it wouldn't have made sense back then. A lot of people claim Hasbro made the Flagg just to show off and get parents talking about what an insanely big toy had just been created.
Haslab might be a viable option for giant prestige toys like that, but it would be a hard sell. If you want to see what could have been you can always haul yourself over to Toy Traders in Canada where they built half of one for their in-store display.