Tigerchic - I think that the post-exercise electrolyte/mineral balance issue goes farther than just salt. Though, I do see where you're coming from.
There's mineral packets that you can get which have some of the essential minerals that you need to replenish after potentially de-mineralising things such as sweating a lot, working out and drinking heaps of water. There's also powder drinks you can buy and take as a post - exercise recovery tool. (I'm not talking stuff you'd buy at any shop with heaps of unneeded added crap and sugar, etc - I just mean the sort of thing you could buy at a health food store or pharmacy.)
In Australia, this sort of thing is made by a practitioner - only company called Metagenics.
I'm not sure of which US company would provide these sorts of products - but a Google search would probably quickly pop up a few.
There's also colloidal minerals (though they taste gross, they're good).
They may also sell similar products in health food stores etc.
PhotoChick - The problem with low cal sports drinks is that even though they often contain the appropriate minerals in the right amounts, they do sometimes have nasty artificial sweeteners, preservatives like sodium benzoate (a carcinogen) and colourings. If you were alluding to a specific kind of low cal drink that doesn't contain these then:
A) my bad, haven't heard of any that aren't unhealthy and taste good/are efficient/easily accessible. and if you do have the name/brand that makes them;
B) please give me the name of said drink, as I'd be interested to try.
Happy re-mineralising. =]