I finally found Leprechaun 4: In Space at I Love Video the other night. It’s not super-great: it’s not even that scary. But, what the hell, it’s the Leprechaun. As someone else said, “It wasn’t scary at all, and if they didn’t throw that random breast shot in there, it would definatly be PG-13 material.”
Looking up the movie, I see that Mark Jones — the Leprechaun writer — is working on another, uh, “edition”: Leprechaun: Back in Da Hood. Also, check out this AV Club interview with Warwick Davis, the leprechaun.