Has there ever been a model of the sperry ball turrent?

I’d like to model one in 1/4 scale or so.

In that large a scale, why not scratch-build?

Never seen any models of just the turrents. I’ve seen some detail work done on 1/48 kits. Until a large 1/32 kit of a bomber is done that is likely the scale you would find them. 1/4 scale would definitely be bigger than a basket ball! Neat idea!