Now this sounds much more interesting than a Farming expansion focusing on crops to this city gal. :smile: I used to visit my mom during fair week when I was a kid, and this sounds very much like that experience. (Even managed to raise an almost champion dwarf rabbit. :wink: )
I think having the fairgrounds as a special lot (like the lab in Strangerville, or the Police station/hospital in Get to Work) would work out better than having to build the thing manually. And I'd be okay with the lack of customization. That said, the lab and the police station can be edited, so the fairgrounds could be too.
Cold as selling livestock sounds ... it is part and parcel of the whole farm life thing. I'm not sure if character values are the right way to go if they use the same interface as the cats and dogs from pets - since we can't actually see that. And it would probably be easier to adapt those mechanics than the parenthood ones.
I'm also not sure how the stadium shows would work, though if they've introduced cars by then, some way to participate in the demolition derby might be fun...