Hey Danny,
I know DVD workouts seem really corny and may not be enough for most conditioned MMA fighters. But I recently bought John Hacklemans "CrossPit" DVD. Hackleman is a big fan of crossfit and this dvd is based off of thier workouts. I am in semi-good shape but poor cardio as of now (trying to change that) and I dont even start my MMA training untill this Friday...so take it for what its worth...But FOR ME, this is a pretty intense cardio workout.
I think Its good to supplement the gym or if you dont have enough time to lift or train on a certain day. The DVD is only $20 and contains 2 workouts. Each only about 35-40 mins long, keeping you working the whole time.
ie) 30 seconds on 10 seconds off for the entire workout. Rotating between push ups, air squats, squat thrusts, intense bag work, pull ups, situps, jump rope ect... Gasses you good before you get on the bag...
Its best if you have a heavy bag and pull up bar. As I said im not in the best shape yet so its killer for me...maybe not for an experienced fighter. Here a link for a quick preview. Its the CROSSPIT one, Not "the pit workout".. Hope it helps..
http://www.youtube.com/watch?v=JazEDkWDFS4