Hey Fog,
I'm with Graybeard on this one. Over 400lb hogs are an inventory item if you know what I mean. I've shot a few in the mid- to - high 300's. 400 pounders usually don't weigh 400 pounds in that very few in my experience are actually weighed...take a look at some of mine...one in particular I shot in NY in 2004...looks huge but actually weighed less than one I shot in 1995 at a preserve in VT.
I'd say if you really want one, call some large acre preserves and put down a deposit. Expect to pay at least 1K or more (there's a premium for their size and because they tend to have really enormous tusks because they are so old and have their testes). Also, expect your taxidermist to curse you.....the armour plate will dull his flesher and the form size for the mount will never be big enough resulting in a hell of a lot of clay!
As far as eating....well...400lb hogs tend to be overweight breeders which means old and tough...generally...you may get a good one, but, not like shooting and eating a 100 pounder.
Also....IMHO...the really big ones don't run all that much and bay up quickly....just like me. ;0)
So...I'd say....shoot something in the mid-200's. They are usually great eating, make a good large shoulder mount and like to run when they have to. I guess what I'm trying to say is...the really big ones look GREAT in the pictures...the mid-large sized ones are a much better hunt and tend to be better to eat.
That being said.....I've got to come clean...I shoot the biggest I can find anytime, anywhere...a pox on me!