Ouch, you've really explored your options! I must admit I've only really looked at places to get blood tests in Melbourne.

It sounds like you didn't keep a copy of the scan results. If I you did have the results handy it would have been worth getting the guys at imminst.org to look at it. In the collective they seem to be an effective resource when it comes to identifying atypical yet not life threatening health issues.

What interests me in your case is whether you get the other benefits of exercise, particularly the neurological ones. Not losing weight from exercise is one thing but I wonder whether you still get the boost to neurogenesis and the increased resilience to stress that exercise provides.