You should figure out what it would cost you to source the parts if you were going to build them yourself, that is your base price. Then you add on labor and a small markup on each part (hub, rim, spokes). I don't know how much those hubs go for, but purchased at an LBS the Deep V's will probably run about $70 each, spokes about $70 also (give or take, assuming $1 spokes, 72 holes) depending on how many holes and color. That right there gets you to $210. Let's just say labor is $30 per wheel (though I think my LBS charges $30 per), which gets us to $280 that leaves $110 for both hubs and markup. IRO charges on their site charges $74 for the hubs. $390 might be a little high, not sure, but it is not way off.
IRO has the benefit of purchasing things in a volume that I presume most LBS's can't get away with.