I am looking for a snap-in window decoration that goes on the inside of the window that looks like the window has several panes. I have seen them in someone's house, but I don't know what they are called, if they are expensive, and if they can be custom made to fit any window. Anybody know?

The ones in my windows came as kits that are made for various standard-size windows. Even if you found this style kit in the right size, you'd have to drill small holes in the wood frame of the windows for them to attach. They have plastic push-in connectors that match up to the holes in the frame.
However, I've seen some connectors that work like push-pins and simply "stick" into the wood frame. They're not very sturdy, but would do OK in windows that you don't open much.

I have been looking for the replacement plastic push pins that hold the frame to the window, any idea where I can find them?

Did you ever find this product? I have wood faux window panes that pin in against the window. They're fairly fragile and warp over time. I need to replace several of them and I can't seem to find them.

I have been looking for these plastic push pins that hold in the faux window panes too. Have gone to just about every hardware store in 30 mi radius with no luck. The push pins in the windows in the house we just purchased have all pretty much broken, gouge the wood frame of the window and don't work well, so not quite sure why I am still looking. I am thinking about alternatives such as a thin strip of adhesive velcro to hold in place or even qlue to put them in permanently, which would make cleaning the windows more difficult. If anyone has any other suggestions, please reply