There are a lot of challenges out there, and I have come across what I would call the 1000 challenge workout.  However, they pertain to weight lifting, and resistance exercises.  These types of challenges are good and I would assume to say they work, even for martial artists.  But I wanted to come up with a 1000 repetition challenge particularly to martial artists.
The Challenge
100 jump rope
100 pushups
100 crunches
100 jab – cross combinations (50 each fighting stance)
100 hook – uppercut combinations (50 each fighting stance)
100 rapid punching ( 50 each fighting stance)
100 front kicks ( 50 each fighting stance)
100 round kicks ( 50 each fighting stance)
100 side kicks ( 50 each fighting stance)
Conclusion
Honestly, this challenge is not that hard, but for some, it may be exactly what you are looking for.  The purpose is to try and push yourself to train harder, fight faster, become stronger.