I know I'm late to the party here but what about retired military working dogs? The husband and I had planned to go that direction but we had a 12 lb little alpha boy to worry about so we went with a puppy. Our next GSD will be a retired MWD though and many of them are ready for a slower pace so do not need all the exercise of younger dogs of any breed and they are very well trained well before you get them.
Live every day like he deploys tomorrow

Proud parent of two furkids:
Dexter - Schnoodle - born 05/02/2009
Neeko - GSD - born 11/16/2012