Also, not quite the same thing, but for a while Farscape's season 4 finale did have to function as the series finale. And what an awful place to leave off.
I thought it would've been a perfectly appropriate ending. I mean, Farscape
was never conventional and always thoroughly weird and wild. It would've been entirely fitting for the series to end with a shocking, frustrating twist that left no doubt that the characters' crazy adventures would continue indefinitely.
Honestly, were it not for the final scene, Bad Timing
would have made a decent "conventional" finale, too. It managed to wrap up Crichton's story in what I thought was a very satisfying way.