I've been slowly trying to gain knowledge on Barndominuims myself. I'm not ready at the present time, but I'm just trying to educate myself until then. I have seen a few threads on here discussing them. Also, if you have Facebook, I'm a member of a closed group, called: "Barndominuim Living", where folks post pics, questions, and answers. Good luck!
I had a friend that had one.
It was a kit steel building, very nice inside and out. Front looked almost like a small house. He had Paint horses of his own and boarded some for other people. If I remember, it was pretty reasonable back then. I haven't seen him in about 20 years so I don't know how well it holds up.
I have seen some ads about steel buildings used as a shop or garage that either had living quarters beside or on top. Should be pretty easy to let the mfg. to erect it and DYI on the inside should be a good deal.
Yeah, it's often made from steel buildings, but also several are made from post frame buildings, or pole barns. It's appealing to me, because you can have a very large shop/garage/living, all in one big building. It's also pretty low maintenance on the outside.
I played around on a simulator from one of the local post frame builders.