Yes, I see your point. And, the more I think about it, the more I think you're on the track of something that could usefully be revived.You're right that rounds are remembered as a kids' thing, and the words we sang as kids were fairly simplistic. So, are there words and lyrics which can clearly be seen as 'grown-up' rounds?
I do apologise for not being at all helpful, but wish you the best of luck with it. - IanB