"Little Joe's" in Grand Blanc. There are actually a few places around here that still have it on tap and have had it for a while so I assume they've gone through multiple kegs.
Oddly enough, I couldn't find it in stores at all; my local bottle shop only received a single case and was charging crazy prices. Cheaper on tap at a restaurant than in bottles at the store. Weird...
The Red Baron in Burton still has hopslam as well. Bill, the owner, just got his federal permit and is brewing and selling his own beer now as well.