This city was done about 3 years ago, so this is a really late submission... It has 16 luxury palaces and 3 blocks of grand insulae, and everything is perfectly stable. 3 tents and 1 shack kind of ruin it, though. =(
I learnt the palace block from Theo and the insula block from Pelagius, both whose building blocks I 'secretly' observed from their playtests of my scenarios. This is late but thanks a lot guys!