Yes. When Repub Abraham Lincoln ran for re-election in 1864 (post-Civil War), he chose Dem Andrew Johnson from TN as his running mate on the so-called "Unity" ticket.

Johnson, you may know, had been the only U. S. Senator from a Confederate state not to have resigned his seat. He had continued to serve TN in the Senate throughout the war. Of course, TN was the last state to have (reluctantly) joined the Confederacy, the first state to have been readmitted, and offered more enlistees to the Union army than did all other Confederate states combined.

As to Kasich and Hickenlooper, as well, the "unity" between those two preceded this stunt. Both are huge "ed reform" folk, especially WRT their support for charter schools. I'm not sure there's much to distinguish the one from the other, really.

I'll volunteer the opinion that there isn't a snowball's chance this duo would tackle the radical reforms the country needs economically, so I'm underwhelmed.