those are proprietary Chess.com pieces designed by me :)
"Club" Piece Style
"Proprietary"? Copyright - for the specific images, okay - but dubious to defend against knockoffs.
You can get a graphic designer to to custom design a set easily converted to any file format, size, color..... that you want. Unless you want something really custom in design the cost should be minimal for such a project. I'm a programmer and don't do a lot of graphic work, but this is something that can sourced out with a quick turnaround. It is very simple graphic work.
Integrating is separate issue, but anything is doable.
Are these available somewhere as png/gif/jpg? They look really nice, and I would like to integrate them into my copy of Scid.