There does appear to be significant economical imbalance, however it would take blood being spilled before powers that be would let any kind of secession stand.
[0] http://www.dailymail.co.uk/news/article-2586531/Venice-votes...
It's difficult to understand what blood would be spilled within the EU. The UN constitutionally stands for the right to self-determination and that needs to be respected.
For now, that's difficult within the EU is because several states are in danger of losing their integrity: UK, Spain, Belgium, Italy, perhaps even Germany. No country wants to let the others split up because of the potential consequences for themselves, so they make political statements supporting the others (but not more than statements).
In the end, one properly official referendum falling on this side will force some fair rules of secession to be drawn up: I don't see any option but to respect these movements.
http://en.wikipedia.org/wiki/Federal_taxation_and_spending_b...
Good thing Minnesota and Florida are so far away from each other. Ya, you betcha!
Shaking up the state borders might give a few states pause, though.