I don't remember where I read it but some amp designers actually think that the best thing is to have an integrated amp with a separate power supply. That is a two box solution but with different separation of what goes in which box.
Another solution could be four boxes, pre and power and then separate power supplies for each. It may be technically better but it is very expensive.
Another solution could be four boxes, pre and power and then separate power supplies for each. It may be technically better but it is very expensive.