hmm.. I like this game. For bigger groups, maybe you can do it like a relay - so have 4 or 5 from each side stand in a line and go one sentence at a time. If you do it in rounds, you can give everyone a chance (i.e. round 1 = the first 4 or 5 from each time, round 2 = the next set, etc).
I'm going to try it next week for my end of semester games day..