Wisconsinite sounds like some sort of flaky mineral.

I’m pretty sure people from Maine are “Mainions”

Source: my uncle works for Maine

It's Sconnie

Arkansan is an interesting one to me.

Is it like Arkanzin (how you would say Kansan plus the Ar- part) or more like Arkanson (with the softer s)?

You occasionally hear/see "Coloradoan" here, too.

South Dakota is wrong, here. We call ourselves "South Dakotants", with a T sount at the end.