If you're just looking for individual DVD's
Give Cathe Friedrich a look.
She has many DVD's to choose from and you can take a sneak peek on her website.
She has different series: beginner, low impact, just cardio, cardio and ST, etc.
Some use extra equipment like steps, slide/glide discs (so be mindful of those). shop.cathe.com/workout_dvds_s/1.htm