I've got a new Ultra Short Course Race Format for you to try. It's called "SUP Derby". (Inspired by ScubaSim!).
Two "Cans", about 50m apart. 10 paddlers. 10 Lap Race, so about 1,000m in total. You can go around the cans either clockwise or counter clockwise.
Get the Video Camera's out, and Board Mounted GoPro's !! Oh, and some Rail Bumper Tape could come in handy.



Edit; Actually, get 10 of those Soft G-Board.... Game On !! It would be an absolute P!SSER !! You could run it close to the shore, and have 1 or 2 judges. You would need some basic rules, maybe;
1) If your board mounts another board, disqualified.
2) If your paddle or board hits another paddler, disqualified (unless it is soft accidental contact of a paddler who has fallen off).
That's probably enough rules....