Maybe in the meantime you can keep checking out the shelters? Those places are very committed to matching homes with appropriate dogs, and if a pooch has been mistreated badly enough to be a danger, they don't sell them on - or they make sure you can give the time to them.

I have a very (previously) badly mistreated dog sitting at my feet right this minute. She is an absolute joy...it's like she appreciates the love she gets even more. The only 'scars' she bears as a result of the mistreatment is that she runs under the table when voices are raised.