There are at least 3 dispensaries/clubs operating in Detroit. One in the Russell Industrial Center, one in Eastern Market, and one on Woodward in New Center. I think the real problem with running a "legit" club in the D is most of your customers aren't going to bother with shelling out for a state MJ card. On top of that, they won't pay dispensary prices, either - they're used to buying grams of brick weed on the corner. Throw in the safety issue and you've got a crappy business plan. I say this as a proud homeowner in the city of Detroit who knows his way around the hood.
Someone came up with the idea of operating a dispensary out of the back room in a strip joint. Security is already taken care of at the door, and you can cross-sell with the existing establishment. I laughed at first, but then I thought "hmmm"...