Does such a thing exist? I mean Adam Adamowickz's artworks for Fallout 3 is present, but I have not found any record of a New Vegas artbook or even just a huge compilation of the concept arts. The most that I have found is the one who designed the Paciencia, Plasma Defender, and the Bozar.

There is. But it comes together with the Game Guide under the name: Fallout New Vegas Collector's Edition by Prima Official Game Guide.