I'd say maybe Canada could join Scotland... but then, the EU with its current border policies is no place to be.
Make it a package deal... The UK keeps Scotland AND Canada re-ups on the (Brit/Can/Aussie/Kiwi) Commonwealth, strengthening ties between the most natural of allies, strategic, economic, and familial.
![Drink up [B-o]](./images/smilies/drinkup.gif)