You don't want to get your hopes up too quickly in a situation like this. Nor do you want to read too much into anything. That said, there have been some interesting developments of late.
After the surgery, Tinker's tail would move to some degree. The doctors felt it was more of a reflex than anything. However, over the past week Tinker has begun wagging his tail on a regular basis. It's obvious that he's controlling it on his own- that it is a neurological response.
We attach a sling to Tinker's back legs in order to take him out for a walk. We raise his back legs while he moves around with his front. This morning he still had the sling on while eating. By holding the sling handle up, I had him standing while he ate. I relaxed the sling and realized he was standing on his own. Finally, after maybe 10 seconds, his legs began to sag and I raised him back up again. It makes us wonder how he's doing this. We know from tests the other day that his front legs are bearing the brunt of his weight.
For the first couple of weeks after the surgery, Tinker's back legs never moved during REM sleep. The rest of his body would be twitching (sometimes accompanied by sleep "barking" -- what we call "boofing" since that's the noise they make :) ), but no reaction from the back legs. Over the last few days, his back legs have begun to move during REM sleep.
All of these things are encouraging. They may be little things, but they are encouraging nonetheless. Tomorrow is Tink's 1st day of physical therapy. Go get 'em dude! :)