I think you need to be careful. If you are trying to teach something new then this is a no no. If you are trying to stress test known techniques it could be a valid plan.
Some may say you are pretty mad suggesting it as you will be in the class that tries it out!
As for karate tabata
We do low kicks roundhouse kicks to bag (1 left, switch sides, 2 right, 3 left etc etc) or just punching on focus mitts or the great 2 punches on the mits, chest to floor, 4 punches, chest to floor 6 punches.......... and so on. Now that really hurts!
There are so many wonderful ways to make ourselves feel rather bad