Damn, James, that is a lousy memory. I'm really sorry. Thank god for D&D getting so many of us through childhood, huh?
Do you remember anything else about that module? I remember not really knowing what to do with it. Like there was this bad-ass beholder civilization, flying around in a beholder shaped-ship, and then… you… well, you see, this ship is full of *beholders* and… um, yeah.
In theory, mage-powered space galleons is cool, but I remember it working a little more like this:
GM: The beholder/githyanki/space gnomes fire the ballista/disintegrate ray/giant miniature space hamster launcher and do 9 points of structural damage! A hole opens up in the hull, exposing your mage.
PCs: Gah! We run below decks, frantically trying to…
GM: And an arrow kills the mage.
PCs: Gah! We run above decks, frantically trying to…
GM: Natural 20! Space catches on fire and everyone takes 10d6 damage…
PCs: Gah! We roll around and…
GM: Psionics turn everyone who isn't a genius into vegetables!
PCs: Erm. The back-up NPC mage-helmsman heads below deck…
GM: A mind flayer boarding party eats his brain and…
PCs: You know what? We just rolled up 1st level guys. Let's have a tavern brawl.
GM: In spaaaaace?
PCs: Uh, no.
Now all this aside… if you played Spelljammer for the whacked-out gonzo insanity of it all, without worrying how any of it worked, made sense, or whatever… and you had a solid adventure formula, probably centered around exploring ancient beholder-shaped space-ships, floating githyanki castles, and so on… you might just have something.