Titan Publishing is based in the UK and they used to let you order direct from them but also they would sell through Amazon here in the USA. I noticed they have the AC: Unity Limited Edition hardcover up on Amazon now, for $60 plus $3.99 shipping. Shows in stock now.
This is certainly a better way to go than before, a few years ago I ordered the Halo: Art of Building Worlds hardcover and they shipped from the UK so they must have added a new distributor here to handle the shipping to U.S. addresses.
http://www.amazon.com/gp/offer-listi...n=new&sr=&qid=