My wife’s iPod mini got stuck on the “connected, eject before disconnecting” screen. She was so upset because this was a replacement for the first bad iPod mini. This time it wasn’t the mini, it was a human error.

To reset the iPod mini, or any iPod for that with the wheel, toggle the top hold switch on and off then press and hold the middle select button and the “menu” button togather for a few seconds (until it resets to the apple logo).
The problem, I’m sure, was failed to disconnect the iPod before ejecting it from the iTunes device list.