The chances of it?

Is there a good/any chance that micro-atx motherboards will be made for the am3+ socket that can actually support AMD's 8 core CPUs anytime soon?

In all likelihood no. I believe AM3+ is done. If AMD decides to actually continue the FX line or reintroduce the Phenom (Phenom III) it will be with a new socket presumably AM4. But by looking at the roadmaps I don't think AM3+ will see much evolution. What we have is what we have. 

Nobody knows ☺