I was cruising around for rowhouse info and found a great resource on rowhomes, the Philadelphia Rowhouse Manual, which was just published this year.
The manual has a lot of great information and renovation guidance for rowhomes. With such a small space there are a lot of constraints on your design, with this manual offering a lot of solutions for the common rowhouse issues (like being so long and skinny). If you are looking to renovate a rowhouse this is definitely worth the time to read. It has info ranging from general roof pitch numbers, rooftop deck info, window anatomy definitions, general kitchen appliance dimensions, stair dimensions, to recommendations for adding a small bathroom.
It would be better if it was from Baltimore, as it has some information on building codes, but beggars can't be choosers. :-)
On an unrelated note, I was looking at an old entry of pictures I've taken of Baltimore. It makes me sad that I'll be selling some camera lenses due to renovations, but desperate times call for desperate measures.