I know where you are talking about, and I would like to offer a suggestion on how to make the most revenue in a low income market.
First, being from Milwaukee we can both agree that the city is trying to clean up and improve the entire city. Miller Park & Potawatomi Bingo Casino, and the painful Marquette Interchange project are large examples of the city trying to 'revive' the city/business in my mind.
So one I feel you are in a good situation down because down the road your low income business district may not be so 'low end' in the future. But I dis-agree with offering products & services to low income family's that are not 'needs.' I feel you have a responsibility as a business owner to shape the future of Milwaukee.
I have down plenty of research on market trends and companies in the rise. One of the largest contributing factors I have found are companies that provide a greater good to their community, city, are having great success. I suggest you find a market that provides a greater good for Milwaukee, especially the low income families around the area.
People do not need electronics, they do need a grocery store & laundry mate. I think if you focus on providing a greater good to Milwaukee and your local community. I have a feeling if you can find a market that helps the local community you will find a profitable market since their is a strong push to improve Milwaukee's economy, plus it is the right thing to do
I think you should read Muhammad Yunus, Banker to the Poor book. He won the Nobel Peace Prize and it all started out by his quest to help the poor get out of poverty & from inevitable death. His whole philosophy was lending money to the poor, his Bank now does over 5 billion in revenue
You should also pick up the current issue of Fast Company (Dec 2006 | Jan 2007) - Social Capitalist Awards. It explains how social organization are finding 'doing the right thing for the world' & 'finding new markets' are the same & very profitable. Proctor & Gamble's PuR water purification product is a very good example of how targeting the developing world and providing a product / service that is needed and helps out countries are extremely profitable markets to be in.
I hope this helps.