I've commissioned someone to make a Nendoroid/Obitsu11 doll for me once. It came out really nice! I got 3 custom face plates and two custom outfits along with custom hair.
I have one! It was commissioned from NieboArte on Etsy. They did an awesome job, he looks like legit merch. It's Nightmare Nny from the Halloween episode of Invader Zim lol.
I purchased a Nendoroid-style version of my FFXIV Lalafell from TopClayArts on Etsy. I really liked the head I got - clay modeling is just about the only way to deal with some of those elaborate FFXIV hairstyles - but I went to add some details that were missing and discovered in extremely the hard way that the paint on the face had not been sealed in any way. A damp cloth took off half his face before I realized what was happening. So I still have a nice head with the fancy hairstyle and pointy ears molded onto it and I just need to hire someone to paint a face on it again. ^^;
I've customized nendoroid faceplates and similar things for myself, but not commissioned anyone, no. My Chibi-Me figure is a Nendoroid I assembled out of various pieces and did some custom painting for, on a YMY body. I have a series of faceplates for her making a bunch of expressions and I modified them with a little paint to look more like a chibi version of me.