Gawd, I LOVED that show...
Gloop! Gleep! Igoo! The funky rhino-bug dude...um...in retrospect, it sounds kind of silly, doesn't it? But I've always, always wanted to DM a campaign based on the Hurculoids.
No advice as to a DVD set, but I know you can get some episodes and partial episodes off of YouTube...if you don't mid the copyright issues. I won't watch bootleg, downloaded movies, for example, but when my daughter wanted to know what "Chicken Boo" was, I went online to find some clips of Animaniacs videos. Bought her the DVD for christmas that year. You'll want to preview any Herculoids stuff you find on You Tube, though, because I'm sure there's some...R-rated fan-created stuff out there.