A lot of large clusters I see in the enterprise are on big VMs or metal (48 core boxes) and so can range from 100-400 for a lot of common medium sized workloads. But at that density you also have to have a workloads with low IO requirements and think about network density. Also, very dense multi tenant dev clusters can easily get above 100 for test environments or when lots of people have created demo apps that mostly sit idle.