Townhomes are great. Detroit should be blanketed in them, provided that they meet certain urban design standards.
The newer Brush Park ones are a great example, or here's one in Chicago:
https://goo.gl/maps/DJeVKcNz7TKcKzNc7
The trick is getting the construction cost low enough that middle-class buyers can afford them. That probably means wood-frame, hardie siding, 1-car parking requirements only, etc.