Why so little in body image stabilization?

Camera manufacturers should not underestimate the marketing clout of IBIS for advanced users. I bought into Sony rather than Nikon solely on the basis of IBIS when I went digital. The Sony NEX cameras don't have it because of the small is all design criterion and because Sony thought the NEX range was for bridge cameras - hopefully they have learned and the NEX-7 successor and FF NEX will have IBIS, even if there is a size penalty. For legacy lenses there is just no alternative.