Something like this one
Building is I suppose an option, but since the idea is to protect users and passerby, I’d be worried about providing a false sense of security if we weren’t careful about design / construction.
I would consider the size of the objects to be coated and then what kinds of coatings would be allowed. The hood linked is a “fume” hood, more than what is needed for applying coatings. There are a number of other potential issues with establishing a spay coating areas.
I would be willing to donate my home made, knock down spray booth if you’re interested. I would suggest spraying only water based poly or other low voc finishes if you decide you want to give it a try.