Sadly, I'm a mere Northerner as well although the more I learn of The South the more I feel kinship with the people and cultures there rather than the land where I'm forced to live at the moment. As a result, I suppose it would be most appropriate to refer to me as 'a great supporter of The South and it's people' but unfortunately I'm no expert on such things....your request would probably be best addressed to our friend stainlessbanner for a much better answer than anything I would be able to give :-)
The various flags of the Confederacy have a glorious past and vary in design and purpose.
There were and continue to be folks in Northern states sympathetic to states rights, home-rule, and sovereignty. A friend of mine born and raised in NY flies his CBF proudly.