So I was recently reading about this in a book about Nebraska history (Nebraska is my home state) and in the 1850's there was a big sectional divide between areas north and south of the Platte River. The South side had more people, but due political influence, Omaha became the capital. Anyway, a number of south siders wanted a resolution to become a part of Kansas. Even the Kansas territory was interested since they thought that they might need Nebraska south of the platte to counter pro slavery men in Kansas. However this motion wasn't even brought up in the legislature, but the rivalry continued until 1867, when Lincoln was made the State Capital.
So what if the land in Nebraska south of the platte was a part of Kansas. What would happen north of the platte. Might Omaha and northern Nebraska be a part of Dakota, or would Nebraska take over what is today SD?