Gen 13 was made into a full-length animated feature in 1998, but, as far as I know, was never released in the US. It's about 1.5 hours long and details the origins of the Gen 13 team, their training, how they came into their powers, etc. The friend I borrowed it from believes it may have been a pilot for an animated series, but given the amount of adult content, I doubt it would fly for an American audience. Though most of the nudity is censored out in the version I saw, there is an extended shower scene, and Fairchild's first transformation is fairly explicit. There's also a great deal of strong language (uncensored).
In spite of the above, the movie is surprisingly well-made. It was directed by Kevin Altieri, best-known for Batman: the Animated Series in 1992, and features the voice talents of Mark Hamill as Threshold, Elizabeth Daily as Freefall, Flea as Grunge, Alicia Witt as Fairchild and John DeLancie as Colonel Lynch. As far as I know, it's only available on VHS in Australia.