Yes, a HUGE addition today - local co-op for all solo campaigns on the shelf! Thanks to kanevan for prompting me to do this.

• Toggle on or off at any stage of a campaign from the main menu (just tick the box).
  
• 2nd player uses Gamepad ONLY. 1st player uses mouse.
  
• Gamepad can match dice and use Dice Ultras. Dragging dice works, as do the ultras' tooltips.
  
• Mouse will ONLY control the sheet, same as the online co-op. If there's no gamepad, you can't match dice if Local Co-op is selected.
  
• Hotswapping a gamepad in seems to work fine, though this may be pad/PC specific so I can't promise it will work for you.
  
• Online Co-op remains an exclusive non-local mode with its own special Scenarios and Endless mode. There is no local co-op Endless yet, I will see what demand is like for that.
  

PLUS I also enabled Remote Play Together in Steam as a way to give Online friends the full co-op campaign experience as well. I have not been able to fully test this yet so please bear with me, and send me feedback. Steam provides guidance on Remote Play Together here: https://help.steampowered.com/en/faqs/view/0689-74B8-92AC-10F2 - however here is a quick primer:

• One player loads up CrossOver and enables the Local Co-op option.
  
• That player brings up the Steam Overlay (Shift+Tab), right-clicks the friend's name and invites them to "Remote Play Together".
  
• If they accept, they will then act as though they are playing on your computer, so their gamepad should work for Local Co-op.
  

It is somewhat reliant on bandwidth from Steam and I have no control over that, but I am hoping it is fast enough for most people.

Enjoy some local co-op fun, all!