I don't have any that are exactly 30 minutes. But Biggest Loser has a couple of videos that break down into cardio of about 25 minutes which is pretty good. I like that the contestants are on there, so it's like "real people" working out with you. Also, Turbo Jam has a 20 minute workout that really KICKS BUTT! Good luck in your search...and I loved looking at your progress pictures. VERY inspiring!!!
Check out the "10 minute solution" series. They have a lot of videos (cardio and otherwise), Each DVD has 5- 10 minute workouts that can be combined in any way you wish to make a workout.
Star Trainer's Cardio has 5- 30 min workouts on it, each in a different style lead by a different instructor. I like Kendall Hogan's workout the most, he gives us options for different intensites and impact.
Exercise tv has alot of free downloads [online] that you can record and than transfer to dve some are 10 min some are 20 min I love all that I have recorede some are cardio some abs some combine scuplt cardio kickbox you name it I love one I have by Cindy Whitmarsh Check out the site its pretty cool! You can order them realley cheap! and they have all kinds of cool stuff I found them from COKE POINTS {when I drank it}