To add to what you are saying, the problem with the Nano was that it was addressed at a market where the average buyer will look at all options available. A car is not a "life necessity" and that alone puts the prospective buyer in a different class. This means that the Nano competes with the other offerings on the market rather than being a separate market unto itself. The Tatas envisaged a separate market developing around the product, which didn't happen, and hence the low sale numbers. What they might want to do is try and "create" the segment they want. How they do it is entirely up to their marketing team, although being a marketeer I might be able to think some ideas up as well.
The Nano stigma you talk about was the average car buyer looking at it and thinking, "That is a terrible car." Wrong audience. But I can understand why they did it though. As a car manufacturer trying out new things, their marketing did tend to see it as a "car market" problem -- hammer, meet nail.
Housing on the other hand is a "life necessity." If the houses Tata is promising are able to deliver on quality, security, repairabilty, and temperature issues, you might have a winner. It will also have to withstand the endless jugaads people are going to subject it to in cramped urban spaces.
On the other hand despite Tata's tall claims, it's difficult to see their marketing team do much about it. I don't see Tata Swach ubiquitously in shops here, nor do they respond to inquiries about their solar cells (I tried). Beyond the brochures and the websites, it's difficult to get Tata to respond to you. This makes most of these announcements pointless.
As an Indian, all I feel is further dejection and the hopelessness of dealing with a bunch of lotus eaters with press releases trying to solve problems of an audience they do not understand.