I'm with velect on this with the 320A, with 2- 200A to subs in the house. It's actually the only panel you'll easily find for this size. Bear (Grizzely) in mind, these panels a huge (36"x48"+), for a residence. I have not done one over-head, nor would I want to. 4" riser and conductors for 320 continuous across the front of a house is just ugly, and a beast to support. If it is on a sizable property, think about locating it with underground in mind, even if remote from the house at a gate house or such. (For meter reading) They have the money to U/G if they have a house that needs something this size, and if they question it show them a 3"-4" weather head and a piece of 350-500MCM, (Cu-Al) they might change thier minds.
