The bead board is custom. It is Tongue and groove poplar with a 1/4" bead routed along one edge.

I have beadboard planks that are made of MDF and come plain or pre-primed. They have varying widths for the bead. I love this product and we are very happy with it so far. In fact, more is being installed in a new addition as I write. The planks are tongue and groove approximate 12" wide and I have a 6" bead. So, each plank looks like 2 boards in width.

I'm sure other places have similar product. We got ours at Muskoka Lumber in Bracebridge (Ontario, Canada) Their website does not have photos but I've linked to the page with some specs for what they carry and they will also do custom according to their site.

Muskoka Lumber Beadboard source

By the way, that inspiration picture is very lovely. It was exactly this type of look that made me source beadboard. I'm told by my contractor that it is easy to work with and goes up very quickly. We got pre-primed so painting and finishing it was very easy as well.

I would just say to be sure to use water resistant MDF and seal it properly because other wise it will swell with exposure to any moisture. I am glad you liked the picture!