Reality is that if you don't have your house under contract, and with a reasonable certainty of it closing, a seller in another state is probably not going to accept your contingency.
However, bridge loans are different critters from second mortgages. Many lender will carry a bridge for you as long as you meet three criteria:
A) you have decent credit (duh)
B) would qualify for the mortgage on the new property once your current home sells, and
C) You have your house listed for sale with a real estate agent
You will pay two sets of closing costs but that's offset by only having to move once.
Short of that the only realistic alternative is to find a small place *cough* extended-stay hotel *cough* that you can rent for a few months while your other home sells. I know your SWMBO has it in her head that this will NOT happen, but sometimes reality is a real pain in the butt whether you want it to be or not.
Brad