Pop City has an article on a neat little infill project in Lawrenceville, from the same team behind Croghan's Edge and a number of other similar projects:
http://www.popcitymedia.com/devnews/row38011613.aspx
Project website:
http://www.epropertiesdev.com/projects/980190970
I tend to like these mix-of-old-and-new infill projects in residential neighborhoods like this (at least when done tastefully), and the way they are adding third floors to the existing modest two-story rowhouses demonstrates how with a little ingenuity it is in fact possible to move these former working class neighborhoods upscale:
Of course that isn't unproblematic for a variety of reasons--these units are apparently going to be sold for $250K, which isn't horrible (just look at what a similar home would go for in a "hot" neighborhood in DC), and it is obviously a lot more affordable than the $375K they plan to ask for the entirely new units. But that is still beyond the means of many area households, and therefore for good or ill this project will contribute to the ongoing gentrification of Lawrenceville.
Nonetheless, I think this is a demonstration that we can in fact largely preserve Pittsburgh's remaining historic rowhouses, no matter how modest, and still meet what the market for urban housing is demanding. And again, in this case the renovations are at least more affordable than the entirely new homes.