I'm so sorry to hear that it hasn't worked out with Scout.
I can surely understand why you wouldn't want her living with you anymore.
As for the people interested in her, I'd ask for veterinary references... and you might even want to get applications from people. It's not "easy" to place a Dane in a good home just because there are people who "want" a Great Dane. (I used to answer emails for a Dane rescue group, just so you know where I am coming from). There is a rescue group here in Athens with Dane experience if you get too frustrated with trying to find a home for Scout yourself. How many homes has she been through?? The next one should be her last, so it will be worth whatever it takes to get her matched up with the right people.
Best of luck... hehe looks like you got pretty lucky with thta lottery thing
and I hope your other dog is feeling better!!!